Metallocene catalyst system suitable for polyolefin elastomer

Abstract

The invention discloses a metallocene catalyst system suitable for a polyolefin elastomer, the metallocene catalyst system comprises metallocene catalyst solid particles and an antistatic agent, the metallocene catalyst solid particles comprise a metallocene compound, an organic boron compound, the antistatic agent and silica gel, and the structural formula of the metallocene compound is shown in the specification; the organic boron compound is N, N-dimethyl phenylammonium tetrakis (perfluorophenyl) borate. According to the metallocene catalyst system, expensive cocatalysts such as MAO or MMAO do not need to be used, the ethylene / alpha-olefin random copolymer (POE) can be prepared under the gas-phase polymerization condition, the consumption of organic boride of the cocatalysts is low, the number of connecting pieces and caking of polymer powder caused by static electricity is small, the particle morphology is good, and the method is suitable for industrial production. The preparation method has a good application prospect in vapor phase polyolefin elastomers, especially in ethylene / alpha-olefin random copolymers (POE).

Description

TECHNICAL FIELD

[0001] The present application relates to a metallocene catalyst system suitable for gas phase polymerization process for preparing polyolefin elastomer, especially ethylene / alpha-olefin random copolymer (POE). BACKGROUND

[0002] Polyolefin elastomer is a kind of polyolefin material copolymerized by ethylene and propylene or other alpha-olefins (such as 1-butene, 1-hexene, 1-octene, etc.). Compared with polyolefin plastic, it has higher content of comonomer in the molecular chain and lower density. At present, polyolefin elastomer mainly includes two categories of ethylene-propylene copolymer and ethylene / alpha-olefin copolymer, among which ethylene-propylene copolymer elastomer includes two types of ethylene-propylene rubber (EPM) and ethylene-propylene-diene rubber (EPDM), and ethylene / alpha-olefin copolymer elastomer mainly includes two types of ethylene / alpha-olefin random copolymer (POE) and ethylene / alpha-olefin block copolymer (OBC). Ethylene / alpha-olefin random copolymer (POE) has unique performance advantages in the emerging photovoltaic adhesive film field, and the market demand is increasing.

[0003] The metallocene catalyst with special structure has the characteristics of narrow molecular weight distribution, strong copolymerization ability, precise controllable chain structure, and high product cleanliness when used for ethylene / alpha-olefin copolymerization, and is the main catalyst type in the existing technology of ethylene / alpha-olefin random copolymer (POE) field. The cocatalyst is mostly MAO or MMAO, but due to the high price and large consumption of cocatalyst MAO or MMAO, the catalyst cost of polymer production is high.

[0004] In the prior art, ethylene / alpha-olefin random copolymer (POE) is mainly produced by homogeneous-solution method. Chinese invention patent CN118221858A discloses a preparation method of a polyolefin elastomer POE for photovoltaic packaging. Ethylene, comonomer, organic solvent, main catalyst and cocatalyst are added to a polymer stirring reaction kettle under anhydrous and anaerobic conditions to obtain the elastomer POE, i.e. the solution method process production. Chinese invention patent CN116789883A discloses a polyolefin elastomer and its application in photovoltaic packaging film. The elastomer preparation step clearly states that the solvent is mixed with alpha-olefin and then injected into the reaction kettle, i.e. the solution polymerization process. The composition prepared by the elastomer has more excellent optical performance, electrical insulation performance and PID resistance performance. Chinese invention patent CN116041598A discloses an olefin polymer for photovoltaic adhesive film and a solution polymerization method thereof. The method obtains an olefin polymer for photovoltaic adhesive film with improved PID resistance performance. Chinese invention patent CN115746746A discloses a polyolefin elastomer composition for photovoltaic packaging film, and the polyolefin elastomer is obtained by a solution polymerization method. By analyzing the relationship between the POE structure and the performance of the polyolefin elastomer composition, the light transmittance, water vapor transmission rate, volume resistivity and other performances of the polyolefin elastomer composition are maintained at a high level. Chinese invention patent CN117567961B discloses an ethylene / alpha-olefin random copolymer for photovoltaic adhesive film and its application. The copolymer has a fast crosslinking speed and high crosslinking degree in the application of photovoltaic adhesive film, and the photovoltaic adhesive film has high light transmittance. The copolymer is prepared by a kettle reactor and a solution polymerization process.

[0005] Chinese invention patent CN119285815 discloses a method for preparing a polyolefin elastomer by a heterogeneous-gas phase method. The polyolefin elastomer is prepared by a coated modified zirconium metallocene main catalyst and butyl aluminum oxane cocatalyst in a gas phase polymerization. The uniformity of the polymer monomer insertion segment is improved, and the light transmittance of the product is also improved.

[0006] The gas phase polymerization process has relatively mild reaction conditions, lower investment in production equipment, lower energy and material consumption in the production process, and relatively low volatile residue in the product, which is a potential preferred process type for producing photovoltaic packaging adhesive film with low volatile content. In the gas phase polymerization reaction, the metallocene polyethylene product is prone to static electricity. In order to avoid negative situations such as wall sticking, caking and difficult discharge of the polymer powder caused by static electricity when producing low-density polyolefin elastomer products, there are higher requirements for the morphology of the supported metallocene catalyst and its polymer particles and the static level in the reaction system.

[0007] Studies have shown that organoboron compounds with adapted structures can activate metallocene compounds for olefin polymerization or copolymerization. However, since the matched organoboron compounds are all solids and have low solubility in low-boiling-point alkane organic solvents such as hexane at conventional polymerization temperatures, their application has been limited to solution polymerization processes. Therefore, researching and developing a heterogeneous metallocene catalyst system composed of metallocene compounds with adapted structures and organoboron compounds, and applying it to the gas-phase preparation of ethylene / α-olefin random copolymers (POE), is of practical significance. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to provide a catalyst system composed of highly active metallocene catalyst solid particles with organoboron compounds as co-catalysts and an antistatic agent for the production of polyolefin elastomers, especially ethylene / α-olefin random copolymers (POE), so as to reduce their production costs.

[0009] To address the aforementioned problems, this invention provides a metallocene catalyst system suitable for polyolefin elastomers, comprising metallocene catalyst solid particles and an antistatic agent. The metallocene catalyst solid particles comprise a metallocene compound, an organoboron compound, an antistatic agent, and silica gel. The structural formula of the metallocene compound is shown in Formula 1. Formula 1; In Formula 1, n is a natural number from 4 to 10; R1 and R2 may be the same or different, and each is independently an aryl group having 6 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms substituted with an alkyl group having 1 to 20 carbon atoms; R3 is an alkyl group having 1 to 20 carbon atoms; R4 is a tertiary amine having an alkyl group having 1 to 10 carbon atoms; A is carbon, silicon, or germanium; the two Xs may be the same or different, and each is independently a halogen or an alkyl group having 1 to 20 carbon atoms. The organoboron compound is N,N-dimethylphenylammonium tetra(perfluorophenyl)borate; The silica gel described is a fumigated silica gel with an average particle size of less than 1 μm. This type of silica gel is prepared by a gas-phase method and typically has a specific surface area of ​​200 m². 2 Approximately / g. This is an example, but not limited to, Cabot's atomized silica gel products such as TS-530, TS-610, and TS-720.

[0010] Preferably, the metallocene compound is any one or more of the following structural formulas: Formula 2; Formula 3; Equation 4; Formula 5; Formula 6; Formula 7.

[0011] Preferably, the metallocene catalyst solid particles are prepared by spray drying and have an average particle size of 5-100 μm.

[0012] Preferably, the metallocene catalyst solid particles comprise 0.2-10% metallocene compound, 5-50% organoboron compound, and 20-80% silica gel by mass percentage, with an average particle size of 5-100 μm.

[0013] Preferably, the metallocene catalyst solid particles comprise 0.5-5% metallocene compound, 20-40% organoboron compound, and 30-60% silica gel by mass percentage, with an average particle size of 10-60 μm.

[0014] Preferably, the method for preparing the metallocene catalyst solid particles includes the following steps: Step a): The metallocene compound of Formula 1 and N,N-dimethylphenylammonium tetra(perfluorophenyl)borate are completely dissolved in an inert organic solvent to obtain a homogeneous liquid. The silica gel is then mixed with the above liquid to obtain the masterbatch to be sprayed. Step b): The masterbatch obtained in step a) is spray-dried to obtain spherical metallocene catalyst particles.

[0015] In the method for preparing the solid particles of the metallocene catalyst, the inert organic solvent may be any one of those capable of dissolving the metallocene compound of Formula 1 and N,N-dimethylphenylammonium tetra(perfluorophenyl)borate, and having a boiling point not higher than 150°C. Generally, tetrahydrofuran is preferred for economic and availability reasons.

[0016] In the preparation method of the metallocene catalyst solid particles, in step a), there are no special requirements for the process of dissolving the metallocene compound and organoboron compound and mixing them with silica gel to prepare the masterbatch to be sprayed. The proportion of additives is determined according to the requirements of the metallocene catalyst. There are no special requirements for the dissolution temperature and time. Any inert organic solvent can be used if it is below the reflux temperature and can dissolve the metallocene compound and organoboron compound. The amount of inert organic solvent added should be sufficient to completely dissolve the metallocene compound and organoboron compound and ensure that the solid content in the subsequent masterbatch is suitable for spray drying to obtain solid particles with good morphology.

[0017] More preferably, step a) specifically involves: adding the metallocene compound and N,N-dimethylphenylammonium tetra(perfluorophenyl)borate to tetrahydrofuran, heating to 50°C-reflux temperature, stirring and dissolving for 0.5-10 hours, and after complete dissolution, adjusting the solution temperature to 20-50°C, adding silica gel, and stirring to mix evenly to obtain the masterbatch to be sprayed; the mass ratio of metallocene compound, organoboron compound, tetrahydrofuran, and silica gel is 0.2-10:5-50:200-1000:20-80.

[0018] More preferably, step a) specifically involves: adding the metallocene compound and N,N-dimethylphenylammonium tetra(perfluorophenyl)borate to tetrahydrofuran, heating to 60°C-reflux temperature, stirring and dissolving for 0.5-10 hours, and after complete dissolution, adjusting the temperature to 30-45°C, adding silica gel, and stirring to mix evenly to obtain the masterbatch to be sprayed; the mass ratio of metallocene compound, organoboron compound, tetrahydrofuran, and silica gel is 0.5-5:20-40:300-500:30-50.

[0019] More preferably, the spray drying process involved in step b) and the equipment and conditions used in the spray drying process are not particularly limited. Any equipment and methods existing in the art that can be used for spray drying organic phase materials can be incorporated into this invention. The spray drying equipment can be a pressure spray dryer, a rotary spray dryer, or a two-fluid spray dryer. The material drying process can be completed in one step by the spray dryer, or one or more other types of drying equipment (such as fluidized bed dryers) can be connected in series after the spray dryer to continue drying until it is completely dried. In small-scale experiments, because two-fluid spray dryers are small in size and have a wide adjustable particle size range, they are often used as experimental platforms for spray drying to prepare microspheres. As an example, a two-fluid spray dryer is used for atomization and drying of the material to be sprayed. The spray drying process is carried out under an inert atmosphere (nitrogen), and the carrier gas is dried nitrogen. The spray drying yield is controlled by the feed flow rate of the masterbatch to be sprayed, the solvent content of the catalyst particles is adjusted by the outlet temperature, the particle size of the catalyst is adjusted by the ratio of the atomizing gas flow rate to the feed flow rate of the masterbatch to be sprayed, and the morphology of the catalyst particles is adjusted by the synergistic effect of drying temperature and masterbatch composition. The inlet temperature of the carrier gas is 120-200℃, the outlet temperature is 70-135℃, the atomizing gas is dried nitrogen, and the pressure of the atomizing gas is 3-6 bar.

[0020] Preferably, the antistatic agent can be one commonly used in olefin polymerization processes. These antistatic agents include, but are not limited to, carboxylates, aliphatic amines, and polysulfones. These antistatic agents can all inhibit the agglomeration of polymer powder caused by static electricity during polymerization. However, from the perspective of antistatic efficiency, antistatic agents containing polysulfone compositions are more effective. The polysulfone composition includes a polysulfone copolymer and at least one component selected from polymeric polyamines and oil-soluble sulfonic acid components. Preferably, the polysulfone composition includes a mixture of polysulfone copolymers, polymeric polyamines, and oil-soluble sulfonic acid.

[0021] The polysulfone copolymer component in the polysulfone composition of the present invention is a polymer, preferably a linear polymer, wherein the structure is considered to be an alternating copolymer of olefin and sulfur dioxide, having a comonomer and olefin arranged end-to-end in a 1:1 molar ratio. Preferably, the polysulfone copolymer is substantially composed of about 50 mol% sulfur dioxide units, about 40-50 mol% units derived from one or more 1-olefins each having about 6-24 carbon atoms, and about 0-10 mol% units derived from olefins having the formula ACH=CHB, wherein A is a group having the general formula -(CH)-COOH, wherein x is 0 to about 17, and B is hydrogen or a carboxyl group (x 2x), provided that when B is a carboxyl group, x is 0, and wherein A and B together can be dicarboxylic anhydride groups.

[0022] Preferably, the weight-average molecular weight of the polysulfone copolymer of the present invention is in the range of 10,000 to 1,500,000, more preferably 50,000 to 900,000. The unit derived from one or more 1-olefins is preferably derived from a straight-chain olefin having 6 to 18 carbon atoms, such as 1-hexene, 1-heptene, 1-octene, 1-decene, 1-dodecene, 1-hexadecene, and 1-octadecene. Examples of units derived from one or more compounds of the general formula ACH=CHB are units derived from maleic acid, acrylic acid, and 5-hexenoic acid. A preferred polysulfone copolymer is 1-decene polysulfone, which has a specific logarithmic viscosity (measured at 30°C as a 0.5 wt% solution in toluene) in the range of about 0.04 dl / g to 1.6 dl / g.

[0023] The polymeric polyamines described in this invention are preferably products of the reaction of N-aliphatic hydrocarbon alkylene diamines or aliphatic primary amines containing at least 8 carbon atoms, and more preferably at least 12 carbon atoms, with epichlorohydrin. Examples of these aliphatic primary amines are those derived from tall oil, beef tallow, soybean oil, coconut oil, and cottonseed oil. Polymeric polyamines derived from the reaction of tallowamine with epichlorohydrin are preferred.

[0024] The oil-soluble sulfonic acid described in this invention is preferably dodecylbenzenesulfonic acid and dinonylnaphthalenesulfonic acid.

[0025] The polysulfone composition of the present invention preferably comprises about 5-70% by weight of polysulfone copolymer, 5-70% by weight of polymeric polyamine and 5-70% by weight of oil-soluble sulfonic acid, with the total of the three components being 100%.

[0026] These types of polysulfone compositions are commercially available. For example, but not limited to, commercially available STADISTM antistatic agents can be selected, with STADISTM 450 or STADISTM 425 being more preferred. There is no specific limit to the amount of antistatic agent added; the minimum should be sufficient to maintain normal production operations by effectively preventing polymer powder agglomeration and ensuring antistatic properties within the reactor. Since antistatic agents can inhibit catalyst polymerization activity, the actual amount added should be slightly higher than the minimum, for example, 5-10% higher, but not too high. Generally, in fumed polyethylene processes, depending on the equipment process conditions and polymer product performance differences, the amount of antistatic agent injected is generally controlled between 0.001-0.05 wt% of the reactants.

[0027] The inventors discovered in their research that the metallocene catalyst solid particles and the polysulfone antistatic agent composition in the metallocene catalyst system of this invention exhibit a good synergistic effect. When applied to the gas-phase polymerization preparation of polyolefin elastomers, it demonstrates high activity and copolymerization performance. By using a spray-drying molding method, the co-catalyst N,N-dimethylphenylammonium tetra(perfluorophenyl)borate and the metallocene compound are assembled into the metallocene catalyst solid particles, with both uniformly distributed within the catalyst particles. Compared to the method of separately introducing the main catalyst and co-catalyst into the reactor for contact activation, this method allows for more thorough contact between the main catalyst and co-catalyst, shortening the activation response time of the main catalyst, improving the polymerization activity of the main catalyst, and also increasing the utilization efficiency of the co-catalyst, thus reducing its usage. Furthermore, within the catalyst solid particles, the co-catalyst N,N-dimethylphenylammonium tetra(perfluorophenyl)borate acts as a binder, significantly improving the strength of the metallocene catalyst solid particles, which are primarily composed of atomized silica gel.

[0028] The metallocene catalyst system described in this invention can be further introduced into the polymerization reaction system in the process of polymerization, with the addition of a small amount of alkylaluminum or alkylaluminoxane as a co-catalyst. However, it should be noted that the metallocene catalyst of this invention already includes organoboron compound co-catalysts. The alkylaluminum or alkylaluminoxane introduced into the polymerization reaction system is mainly used to remove water and other impurities from the reaction system.

[0029] This invention also provides the application of the above-mentioned metallocene catalyst system suitable for polyolefin elastomers in the gas-phase preparation of polyolefin elastomers.

[0030] The metallocene catalyst system of the present invention has the advantages of high activity, good copolymerization performance, good particle morphology, less agglomeration due to electrostatics, no need to use MAO or other co-catalysts, and lower production cost when used in polyolefin elastomers. Attached Figure Description

[0031] Figure 1 Here is a scanning electron microscope image of the solid particles of the metallocene catalyst in Example 1; Figure 2 The image shows a scanning electron microscope (SEM) image of the solid particles of the metallocene catalyst in Comparative Example 1. Figure 3 This is a scanning electron microscope image of the polymer powder from Example 1. Detailed Implementation

[0032] To make the present invention more apparent and understandable, preferred embodiments are described in detail below with reference to the accompanying drawings.

[0033] The testing methods for each embodiment are as follows: (1) The melt index (MI) of the polymer was tested at 190℃ and 2.16kg load according to the test standard GB / T3682.1-2018.

[0034] (2) The bulk density (BD) of the polymer powder was tested according to the method specified in the test standard GB / T 1636-2008.

[0035] (3) Polymer powder sieving shall be performed in accordance with the method specified in test standard GB / T 6003.1-2022.

[0036] (4) The polymer density was tested using a densitometer (impregnation method METTLER).

[0037] Synthesis of metallocene compounds in Examples 1-5 (1H NMR measurements were performed using a Bruker Ascend 400M nuclear magnetic resonance spectrometer): The structural formula of the metallocene compound is: .

[0038] Step 1-1: Synthesis of 4-(6-(dichloro(methyl)silyl)hexyl)-N,N-dimethylaniline In a flask, 4-(6-bromohexyl)-N,N-dimethylaniline (5.00 g, 25 mmol) and Mg (1.22 g, 50.2 mmol) were added to THF (25 mL), and the mixture was stirred at 70 °C for 4 hours. In another flask, MeSiCl3 (7.47 g, 50.0 mmol) was dissolved in THF (75 mL), and the mixture was slowly added dropwise at 0 °C for 1 hour. The mixture was then stirred overnight at room temperature, and saturated NaHCO3 was added. Water was removed with anhydrous MgSO4, and the resulting solution was concentrated under reduced pressure to obtain a white solid, 4-(6-(dichloro(methyl)silyl)hexyl)-N,N-dimethylaniline (4.80 g, 82%). The 1H NMR is as follows: 1H NMR (500MHz, CDCl3, 7.24ppm): 0.99 (3H, s), 3.01 (6H, s), 6.75 (2H, d), 7.57 (2H, d) Steps 1-2: Synthesis of 4-(6-(bis(4-(4-(tert-butyl)phenyl)-2-methyl-1H-inden-1-yl)(methyl)silyl)hexyl)-N,N-dimethylaniline 4-(4-(tert-butyl)phenyl)-2-methyl-1H-indene (10.3 g, 39.3 mmol) and CuCN (176 mg, 1.97 mmol) were dissolved in toluene (90 mL) and THF (12 mL) under argon (Ar) atmosphere. The solution was cooled to -30 °C, and n-butyllithium (2.5 M hexane solution, 16.5 mL) was slowly added. The mixture was stirred at this temperature for about 10 minutes, and then heated to room temperature and stirred for 2 hours. The resulting 4-(6-(dichloro(methyl)silyl)hexyl)-N,N-dimethylaniline (4.80 g, 20.5 mmol) in toluene (30 mL) was added to the solution, and the mixture was stirred overnight at room temperature. After the reaction was complete, MTBE and water were added, and the organic layer was separated. The obtained organic layer was dried over anhydrous MgSO4 and concentrated to give 4-(6-(bis(4-(4-(tert-butyl)phenyl)-2-methyl-1H-inden-1-yl)(methyl)silyl)hexyl)-N,N-dimethylaniline (13.8 g, 100%), as a white solid. The 1H NMR is as follows: 1H NMR (500MHz, CDCl3, 7.24ppm): 0.00-0.07(3H,m), 1.49-1.52(18H,m), 2.46-2.49(6H,m), 3.00(3H,s), 3.02(3H,s), 4.23-4.39(2H,m), 6.50-7.52(20H,m) Steps 1-3: Synthesis of [4-(6-(bis(4-(4-(tert-butyl)phenyl)-2-methyl-1H-inden-1-yl)(methyl)silyl)hexyl)-N,N-dimethylaniline]zirconium dichloride Under argon (Ar) atmosphere, 4-(6-(bis(4-(4-(tert-butyl)phenyl)-2-methyl-1H-inden-1-yl)(methyl)silyl)hexyl)-N,N-dimethylaniline (6.74 g, 9.83 mmol) was added to a 50 mL Schlenk flask and dissolved in diethyl ether (8.2 mL). The temperature was lowered to -78 °C, and n-butyllithium (2.5 M in hexane, 8.1 mL) was added, followed by stirring at room temperature for 2 hours. At -78 °C, ZrCl4 (2.29 g, 9.83 mmol) in a Tol / diethyl ether (24.6 mL / 8.2 mL) slurry was slowly added to the ligand solution, the temperature was raised to room temperature, and the mixture was stirred overnight. The solvent was distilled under reduced pressure to dissolve the ligand in CH2Cl2, and the solution was filtered to remove LiCl. The filtrate was concentrated, and the resulting crude product was saturated with CH2Cl2. Two volumes of hexane were added, and the mixture was recrystallized at -20°C for 15 hours. Subsequently, when a yellow solid formed, it was filtered and washed twice with hexane to obtain [4-(6-(bis(4-(4-(tert-butyl)phenyl)-2-methyl-1H-inden-1-yl)(methyl)silyl)hexyl)-N,N-dimethylaniline]zirconium dichloride (225 mg, 30%, r / m > 20 / 1). The 1H NMR is as follows: 1H NMR (500MHz, CDCl3, 7.24ppm): 1.30–1.40 (21H, m), 2.00 (3H, s), 2.33 (3H, s), 3.10 (6H, s), 6.85–7.94 (18H, m) Example 1 (1) Catalyst preparation Preparation of metallocene compound solution: Under nitrogen protection, accurately weigh 50g of the synthesized metallocene compound [4-(6-(bis(4-(4-(tert-butyl)phenyl)-2-methyl-1H-inden-1-yl)(methyl)silyl)hexyl)-N,N-dimethylaniline]zirconium dichloride and 300g of N,N-dimethylphenylammonium tetra(perfluorophenyl)borate (commercially available) and transfer them to a glass reactor that has been fully purged with nitrogen. Add 8L of dehydrated and purified tetrahydrofuran, start stirring, heat to 70°C, react for 30min and stir until completely dissolved, then cool to 40°C and wait for the material to dissolve. Preparation of masterbatch to be sprayed: Accurately weigh 1 kg of fumigated silica gel TS-610, transfer it to a glass reactor, and fully replace the air carried in the system with nitrogen; transfer the previously obtained solution to the glass reactor and stir and mix it with the fumigated silica gel for 30 min to obtain the masterbatch to be sprayed; Spray drying: The masterbatch obtained in the previous step was spray-dried using a spray dryer (OM-TS500) to obtain solid microspheres. The spraying conditions were: carrier gas inlet temperature 155℃, outlet temperature 108℃, masterbatch feed pump opening 35%, and atomizing gas flow rate 6L / h. 1.49 kg of spherical metallocene catalyst particles were collected in the product collection tank. The average particle size D50 was 27.2 μm. The morphology images characterized by scanning electron microscopy are shown below. Figure 1 As shown.

[0039] (2) Aggregation Ethylene, hydrogen, and 1-butene are continuously added to a Ф300 gas-phase fluidized bed reactor according to the partial pressure control target of ethylene:1-butene:hydrogen:nitrogen = 0.55 MPa:0.16 MPa:0.05 MPa:1.09 MPa; the concentration of triethylaluminum in the reactor is controlled at 10 ppm; the yield is set at 30 kg / h; and STADIS is used as the antistatic agent. TM A 425 polysulfone composition was added at 0.02% (wt) of the (ethylene + 1-butene) feed amount; the polymerization temperature was 55℃, the average catalyst residence time was 4 hours, and the total pressure of the reaction system was 1.85 MPa. After the reaction reached steady state, the polymer powder was collected, and the polymerization activity of the catalyst was calculated. The obtained polyethylene powder was vacuum dried at 50℃ for 4 hours, and relevant properties were tested. The polymerization properties are shown in Table 1, the sieving results of the polymer powder are shown in Table 2, and the morphology of the polymer powder is shown in Table 3. Figure 3 As shown.

[0040] Example 2 (1) Catalyst preparation Preparation of metallocene compound solution: Under nitrogen protection, accurately weigh 100g of the synthesized metallocene compound [4-(6-(bis(4-(4-(tert-butyl)phenyl)-2-methyl-1H-inden-1-yl)(methyl)silyl)hexyl)-N,N-dimethylaniline]zirconium dichloride and 300g of N,N-dimethylphenylammonium tetra(perfluorophenyl)borate (commercially available) and transfer them to a glass reactor that has been fully purged with nitrogen. Add 8L of dehydrated and purified tetrahydrofuran, start stirring, heat to 70°C, react for 30min and stir until completely dissolved, then cool to 40°C and wait for the material to dissolve. Preparation of masterbatch to be sprayed: Accurately weigh 1 kg of fumigated silica gel TS-610, transfer it to a glass reactor, and fully replace the air carried in the system with nitrogen; transfer the previously obtained solution to the glass reactor and stir and mix it with the fumigated silica gel for 30 min to obtain the masterbatch to be sprayed; Spray drying: The masterbatch obtained in the previous step was spray dried using a spray dryer (OM-TS500) to obtain solid microsphere particles. The spraying conditions were: carrier gas inlet temperature 160℃, outlet temperature 108℃, masterbatch feed pump opening 35%, and atomizing gas flow rate 7L / h. 1.32kg of spherical metallocene catalyst particles were collected in the product collection tank, with an average particle size D50 of 25.9μm.

[0041] (2) Aggregation Same as Example 1.

[0042] Example 3 (1) Catalyst preparation Same as Example 1.

[0043] (2) Aggregation Ethylene, hydrogen, and 1-butene are continuously added to a Ф300 gas-phase fluidized bed reactor according to the partial pressure control target of ethylene:1-butene:hydrogen:nitrogen = 0.55 MPa:0.10 MPa:0.07 MPa:1.1 MPa; the triethylaluminum concentration in the reactor is controlled at 10 ppm; the yield is set at 30 kg / h; and STADIS is used as the antistatic agent. TM A 425 polysulfone composition was added at 0.01% (wt) of the (ethylene + 1-butene) feed amount; the polymerization temperature was 58℃, the average catalyst residence time was 4 hours, and the total pressure of the reaction system was 1.85 MPa. After the reaction reached steady state, the polymer powder was collected, and the polymerization activity of the catalyst was calculated. The obtained polyethylene powder was vacuum dried at 50℃ for 4 hours, and its relevant properties were tested. The polymerization properties are shown in Table 1, and the sieving results of the polymer powder are shown in Table 2.

[0044] Example 4 (1) Catalyst preparation Same as Example 1.

[0045] (2) Aggregation Ethylene, hydrogen, and 1-butene are continuously added to a Ф300 gas-phase fluidized bed reactor according to the partial pressure control target of ethylene:1-butene:hydrogen:nitrogen = 0.55 MPa:0.15 MPa:0.09 MPa:1.09 MPa; the triethylaluminum concentration in the reactor is controlled at 10 ppm; the yield is set at 30 kg / h; and STADIS is used as the antistatic agent. TM A 425 polysulfone composition was added at 0.05% (wt) of the (ethylene + 1-butene) feed amount; the polymerization temperature was 60℃, the average catalyst residence time was 4 hours, and the total pressure of the reaction system was 1.85 MPa. After the reaction reached steady state, the polymer powder was collected, and the polymerization activity of the catalyst was calculated. The obtained polyethylene powder was vacuum dried at 50℃ for 4 hours, and its relevant properties were tested. The polymerization properties are shown in Table 1, and the sieving results of the polymer powder are shown in Table 2.

[0046] Example 5 (1) Catalyst preparation Same as Example 1.

[0047] (2) Aggregation Ethylene, hydrogen, and 1-hexene are continuously added to a Ф300 gas-phase fluidized bed reactor according to the partial pressure control target of ethylene:1-hexene:hydrogen:nitrogen = 0.55 MPa:0.12 MPa:0.05 MPa:1.09 MPa; the triethylaluminum concentration in the reactor is controlled at 10 ppm; the yield is set at 30 kg / h; and STADIS is used as the antistatic agent. TM A 425 polysulfone composition was added at 0.03% (wt) of the (ethylene + 1-butene) feed amount; the polymerization temperature was 50℃, the average catalyst residence time was 4 hours, and the total pressure of the reaction system was 1.85 MPa. After the reaction reached steady state, the polymer powder was collected, and the polymerization activity of the catalyst was calculated. The obtained polyethylene powder was vacuum dried at 50℃ for 4 hours, and its relevant properties were tested. The polymerization properties are shown in Table 1, and the sieving results of the polymer powder are shown in Table 2.

[0048] Comparative Example 1 (1) Catalyst preparation Preparation of metallocene compound solution: except for the absence of N,N-dimethylphenylammonium tetra(perfluorophenyl)borate, the preparation is the same as in Example 1.

[0049] Preparation of masterbatch to be sprayed: Accurately weigh 1 kg of fumigated silica gel TS-610, transfer it to a glass reactor, and fully replace the air carried in the system with nitrogen; transfer the previously obtained solution to the glass reactor and stir and mix it with the fumigated silica gel for 30 min to obtain the masterbatch to be sprayed; Spray drying: The masterbatch obtained in the previous step was spray-dried using a spray dryer (OM-TS500) to obtain solid microspheres. The spraying conditions were: carrier gas inlet temperature 155℃, outlet temperature 108℃, masterbatch feed pump opening 35%, and atomizing gas flow rate 6L / h. Only 0.36kg of solid product was collected in the product collection tank, and it was in an amorphous state. Its morphology as characterized by scanning electron microscopy is shown in the image below. Figure 3 As shown, this indicates that atomized droplets are unlikely to form high-strength spherical particles during the drying process.

[0050] Comparative Example 2 (1) Catalyst preparation Except for replacing 50g of zirconium dichlorodichloro with the metallocene compound [4-(6-(bis(4-(4-(tert-butyl)phenyl)-2-methyl-1H-indene-1-yl)(methyl)silyl)hexyl)-N,N-dimethylaniline]zirconium dichloride of the present invention, the rest is the same as in Example 1.

[0051] (2) Aggregation Same as Example 1.

[0052] Comparative Example 3 (1) Catalyst preparation Same as Example 1.

[0053] (2) Aggregation Except for the absence of an antistatic agent, everything else is the same as in Example 1.

[0054] Comparative Example 4 (1) Catalyst preparation Under nitrogen protection, accurately weigh 1 kg of pretreated silica gel carrier (Grace955) and transfer it to a glass reactor that has been fully purged with nitrogen. Add 10 L of dehydrated and purified toluene. Stir to disperse it evenly, then add 2 L of methylaluminoxane (1.5 M toluene solution) and stir at 30 °C for 20 min to obtain chemically activated silica gel carrier.

[0055] Under nitrogen protection, 50 g of the synthesized metallocene compound [4-(6-(bis(4-(4-(tert-butyl)phenyl)-2-methyl-1H-inden-1-yl)(methyl)silyl)hexyl)-N,N-dimethylaniline]zirconium dichloride was accurately weighed and added to a chemically activated silica gel / toluene suspension. The mixture was stirred at 30 °C for 60 min. After the reaction was completed, the mixture was allowed to stand for 30 min, and after separation, the liquid was filtered off. The liquid was washed twice with 10 L / time of dehydrated toluene and then twice with 10 L / time of dehydrated hexane. The obtained solid was vacuum dried at room temperature for 2 hours to obtain the supported metallocene catalyst.

[0056] (2) Aggregation Ethylene, hydrogen, and 1-butene were continuously added to a Ф300 gas-phase fluidized bed reactor according to the partial pressure control target of ethylene:1-butene:hydrogen:nitrogen = 0.55 MPa:0.16 MPa:0.05 MPa:1.09 MPa. The triethylaluminum concentration in the reactor was controlled at 10 ppm. The feed rate of the co-catalyst N,N-dimethylphenylammonium tetra(perfluorophenyl)borate was correlated with the solid particle rate of the metallocene catalyst and the same as the mass feed rate, with a yield set at 30 kg / h. The antistatic agent was STADISTM425 polysulfone composition, added at 0.02% (wt) of the (ethylene + 1-butene) feed amount. The polymerization temperature was 55℃, the average residence time of the catalyst was 4 hours, and the total pressure of the reaction system was 1.85 MPa. After the reaction reached steady state, the polymer powder was collected, and the polymerization activity of the catalyst was calculated. The obtained polyethylene powder was vacuum dried at 50℃ for 4 hours, and the relevant properties were tested. The test results are shown in Table 1.

[0057] Table 1

[0058] Table 2 Polymer Powder Sieving

[0059] The metallocene catalyst system of this invention does not require expensive co-catalysts such as MAO or MMAO. As can be seen from the polymerization data in Table 1, the metallocene catalyst system of this invention has good copolymerization performance and can prepare ethylene / α-olefin random copolymers (POE) under gas-phase polymerization conditions. Moreover, the consumption of organoborides as co-catalysts is low, and the polymer powder has good morphology. As can be seen from Table 2, when the metallocene catalyst system of this invention is used for gas-phase polymerization to prepare ethylene / α-olefin random copolymers (POE), there is less agglomeration of polymer powder due to electrostatics, indicating that it has good application prospects in the gas-phase preparation of polyolefin elastomers, especially ethylene / α-olefin random copolymers (POE).

Claims

1. A metallocene catalyst system suitable for polyolefin elastomers, characterized in that, The mixture includes solid particles of a metallocene catalyst and an antistatic agent. The solid particles of the metallocene catalyst include a metallocene compound, an organoboron compound, an antistatic agent, and silica gel. The structural formula of the metallocene compound is shown in Formula 1. Formula 1; In Formula 1, n is a natural number from 4 to 10; R1 and R2 may be the same or different, and each is independently an aryl group having 6 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms substituted with an alkyl group having 1 to 20 carbon atoms; R3 is an alkyl group having 1 to 20 carbon atoms; R4 is a tertiary amine having an alkyl group having 1 to 10 carbon atoms; A is carbon, silicon, or germanium; the two Xs may be the same or different, and each is independently a halogen or an alkyl group having 1 to 20 carbon atoms. The organoboron compound is N,N-dimethylphenylammonium tetra(perfluorophenyl)borate; The silica gel is a fumigated silica gel with an average particle size of less than 1 μm.

2. The metallocene catalyst system suitable for polyolefin elastomers as described in claim 1, characterized in that, The metallocene compound is any one or more of the following structural formulas: Formula 2; Formula 3; Equation 4; Formula 5; Formula 6; Formula 7.

3. The metallocene catalyst system suitable for polyolefin elastomers as described in claim 1, characterized in that, The metallocene catalyst solid particles were prepared by spray drying and had an average particle size of 5-100 μm.

4. The metallocene catalyst system suitable for polyolefin elastomers as described in claim 1 or 3, characterized in that, The solid particles of the metallocene catalyst contain 0.2-10% metallocene compound, 5-50% organoboron compound, and 20-80% silica gel by mass percentage, with an average particle size of 5-100 μm.

5. The metallocene catalyst system suitable for polyolefin elastomers as described in claim 1 or 3, characterized in that, The metallocene catalyst solid particles comprise, by mass percentage, 0.5-5% metallocene compounds, 20-40% organoboron compounds, and 30-60% silica gel, with an average particle size of 10-60 μm.

6. The metallocene catalyst system suitable for polyolefin elastomers as described in claim 1, characterized in that, The method for preparing the metallocene catalyst solid particles includes the following steps: Step a): The metallocene compound of Formula 1 and N,N-dimethylphenylammonium tetra(perfluorophenyl)borate are completely dissolved in an inert organic solvent to obtain a homogeneous liquid. The silica gel is then mixed with the above liquid to obtain the masterbatch to be sprayed. Step b): The masterbatch obtained in step a) is spray-dried to obtain spherical metallocene catalyst particles.

7. The metallocene catalyst system suitable for polyolefin elastomers as described in claim 6, characterized in that, Step a) specifically involves: adding the metallocene compound and N,N-dimethylphenylammonium tetra(perfluorophenyl)borate to tetrahydrofuran, heating to 50°C-reflux temperature, stirring and dissolving for 0.5-10 hours, and after complete dissolution, adjusting the solution temperature to 20-50°C, adding silica gel, and stirring to mix evenly to obtain the masterbatch to be sprayed; the mass ratio of metallocene compound, organoboron compound, tetrahydrofuran, and silica gel is 0.2-10:5-50:200-1000:20-80.

8. The metallocene catalyst system suitable for polyolefin elastomers as described in claim 6, characterized in that, Step a) specifically involves: adding the metallocene compound and N,N-dimethylphenylammonium tetra(perfluorophenyl)borate to tetrahydrofuran, heating to 60°C-reflux temperature, stirring and dissolving for 0.5-10 hours, and after complete dissolution, adjusting the temperature to 30-45°C, adding silica gel, and stirring to mix evenly to obtain the masterbatch to be sprayed; the mass ratio of metallocene compound, organoboron compound, tetrahydrofuran, and silica gel is 0.5-5:20-40:300-500:30-50.

9. The metallocene catalyst system suitable for polyolefin elastomers as described in claim 1, characterized in that, The antistatic agent is a polysulfone composition.

10. The application of the metallocene catalyst system for polyolefin elastomers as described in any one of claims 1-8 in the gas-phase preparation of polyolefin elastomers.

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