Improved in-situ MAO-derived silica-supported single-site metallocene catalyst

Abstract

This disclosure relates to supported catalyst systems for olefin polymerization, catalyst system precursors, methods for producing these precursors and catalyst systems, and polyolefins formed from these catalyst systems.

Description

[0001] Cross - reference to related applications

[0002] This application claims the benefit of and priority to U.S. Provisional Application No. 63 / 117,337, filed on November 23, 2020, the disclosure of which is incorporated herein by reference. Technical Field

[0003] The present disclosure relates to supported catalyst systems for olefin polymerization, catalyst system precursors, methods of producing these precursors and catalyst systems, and polyolefins formed from these catalyst systems. Background Art

[0004] Polyolefins are widely used due to their robust physical properties. For example, various types of polyethylene (including high density, low density and linear low density polyethylene) are the most commercially useful. Polyolefins are typically prepared with a catalyst (mixed with one or more other components to form a catalyst system) that promotes the polymerization of olefin monomers in a reactor (such as a gas phase reactor).

[0005] Methylaluminoxane (or MAO) is the most popular activator supported on silica for activating single-site catalyst precursors, such as metallocenes, to form active solid catalysts used in commercial gas phase reactors, thereby producing single-site polyolefin resins. Commercial MAO is usually sold as a toluene solution because MAO is easily soluble in toluene. Other solvents have been tried without success. For example, donor-containing solvents (e.g., ether or THF) deactivate MAO. Solvents containing active protons (e.g., alcohols) react and destroy MAO. Aliphatic solvents (e.g., hexane) are known to precipitate MAO.

[0006] Therefore, commercially available MAO is typically provided as a toluene solution, which is unstable and requires special handling and refrigeration because MAO(Al4O3Me6)4(TMA) n (n=1, 2) (Sinn et al. (1999) "Formation, Structure, and Mechanism of Oligomeric Methylaluminoxane", in Kaminsky (ed.), Metalorg. Cat. for Synth. & Polym., Springer-Verlag, p. 105) into a more stable non-reactive MAO gel (Al3O3Me3) x (Energy curve see Figure 1)。Commercially available MAO has a short lifespan, typically less than a week under ambient conditions and less than twelve months when refrigerated, because even when refrigerated, it has a tendency to undergo compositional changes (such as gelling). Commercially available MAO toluene solutions are typically stored in cold environments, such as at -20°C to -30°C, to reduce gelling. Thus, the complex procedures / reaction conditions for increasing the ratio of reactive MAO to inactive gelled MAO during MAO production and the low-temperature conditions required to reduce the MAO gelling process during commercial MAO storage / transportation result in very high commercial MAO manufacturing costs. The high cost and complex handling procedures of the MAO solution are considered to be the main bottleneck in the growth of the single-site polyolefin market.

[0007] Exemplary references include: U.S. Patent Nos. 4,937,217; 5,006,500; 7,910,764; 8,354,485; 8,575,284; 9,090,720; U.S. Publication No. 2016 / 0355618; WO 2016 / 170017; Luo, Jain, and Harlan, ACS Annual Meeting, Conference Abstracts PMSE 126 and INOR 1169 [ACS Annual Meeting, Conference Abstracts PMSE 126 and INOR 1169], April 2 - 6, 2017; and Sinn et al. (1999) “Formation, Structure, and Mechanism of Oligomeric Methylaluminoxane [Formation, Structure, and Mechanism of Oligomeric Methylaluminoxane]”, in Kaminsky (ed.), Metalorg. Cat. for Synth. & Polym. [Metal-organic Catalysts for Synthesis and Polymerization], Springer-Verlag [Springer-Verlag], page 105.

[0008] Accordingly, there is a need for new catalyst systems that can provide performance similar to that of conventional MAO-derived catalyst systems, including good productivity and good operability, while eliminating the complexity of solution MAO production and handling. There is also a need for low-cost methods for forming such catalyst systems and for controlling both the catalyst system formation and polymerization conditions to obtain the desired polymer properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 (Fig. 1) is a schematic diagram showing both an illustrative reactive MAO formation and a non-reactive MAO gel formation energy curve.

[0010] Figure 2(Fig.2) shows the H1NMR spectra of the in-situ sMAO supernatant before (a) and after the 60 °C heat treatment described in Example 34.

[0011] Figure 3 (Fig.3) The broad MAO-like peak (a) in the supernatant, compared to the broad MAO-like peak (b) of MAO extracted from in-situ sMAO with THF, both in THF-d8.

[0012] Figure 4 (Fig.4) depicts the relationship between the resin bulk density and XPS in the pilot-scale R122 experiment.

[0013] Figure 5 (Fig.5) depicts the relationship between the resin bulk density and XPS in the pilot-scale R125 experiment.

[0014] Figure 6 (Fig.6) depicts the CD of polymers from M2 in-situ sMAO relative to the MWD and 1-hexene distribution (CD) of polymers derived from conventional sMAO.

[0015] Figure 7 (Fig.7) depicts the CD relationship from the solid-to-supported MAO ratio as described in Reference Example 33.

[0016] Figure 8 (Fig.8) depicts the CD change of polymers of M1 on in-situ sMAO heated in the presence of TMA relative to that without TMA.

[0017] Figure 9 (Fig.9) depicts the CD of polymers of M1 catalyst on different in-situ sMAO relative to a reference.

[0018] Figs. 10a and 10b (Fig.10a and Fig.10b) depict 6.7 (mmol water / g silica)-derived in-situ sMAO (a) relative to 8.9 (mmol water / g silica)-derived in-situ sMAO (b).

[0019] Figure 11 (Fig.11) depicts the TMA uptake achieved by reaction with silica-water in Comparison 1. Detailed Description

[0020] This disclosure provides one or more methods for controlling catalyst formation to form a better in-situ loaded MAO-based catalyst system, which has improved catalyst activity, polymer bulk density, catalyst operability in gas-phase or slurry-phase polymerization reactors (e.g., controlling fouling and catalyst solid mobility), polymer properties (e.g., composition distribution (CD), polymer density, MI, and MIR), and control of polymerization reactor conditions to obtain target polymer properties. A specific method is to add wet silica in the form of a viscous slurry or solid to a cold TMA solution. If the slurry is transported to the reactor over a long distance (such as through a pipe (especially with uneven diameter changes or sharp-turn caps)), the wet silica slurry may need to have a certain viscosity to prevent silica sedimentation during slow slurry addition, although higher viscosity may not be required for short-distance addition. The viscous silica slurry can be obtained by using a heavy hydrocarbon solvent (such as Hydrobrite oil) to form a viscous slurry that can be added in ambient conditions, or using a light hydrocarbon (such as C5, C6, or C7 solvents) to form a viscous slurry under cooling. A high solid percentage (e.g., about 25%-30%) in a light hydrocarbon solvent may have a high viscosity in ambient conditions, and the easy evaporation of the low-boiling solvent may cause local wet cake formation in the slurry delivery system (e.g., in the slurry pump or pipe elbows), which may complicate the slurry addition. Details of the wet silica addition method are provided herein, including cold silica slurry addition with a low-boiling solvent; ambient silica slurry addition with a high-viscosity solvent; and solid addition.

[0021] In a specific method, a water-carrying carrier can be formed. For a carrier with a surface area in the range of 100 - 400 m 2 / g, the water loading is 3 - 9 (mmol water / g carrier), or for a carrier with a surface area in the range of 400 - 800 m 2 / g, the water loading is 5 - 18 (mmol water / g carrier), provided that at least 60% of the pores in the carrier have a diameter of at least 60 Å or greater, and the total pore volume is in the range of 0.9 - 3 mL / g. This is a control of the MAO loading to avoid overloading (where the pores are completely filled with no space for the catalyst to enter and MAO spills out (which is a reactor fouling factor)) or a low loading that impairs activity; the larger the surface area of the silica, the more MAO can be loaded.

[0022] The supported silica hydrate in solid or slurry form can be treated in a closed container at 40°C to 100°C for at least 10 minutes, or in a closed or open container at 0°C to 40°C for at least 30 minutes. This allows water to be evenly distributed within the pores to obtain a good MAO distribution related to operability; a poor MAO distribution may lead to the formation of hollow points of the polymer resin (reducing the resin bulk density) and high water points that give rise to highly concentrated MAO points (generating local high heat and reducing the polymer Mw).

[0023] The supported silica hydrate can be contacted with a mono- or polyalkylaluminum solution in solid or slurry form, the solution containing at least 50 mol% TMA based on the total Al, and the solution is cooled to a temperature within the range of -5°C to -60°C, provided that for a water loading of 3 - 7 mmol / g, the temperature is -5°C or lower, and for a water loading higher than 7 mmol / g, the temperature is -10°C or lower, and the condition also lies in that at least 60% of the loaded MAO is formed in an environment where the TMA:water ratio is 1:0.75 or higher. A greater water loading results in more exotherm and requires more powerful cooling to maintain a low temperature, thus restricting gel formation.

[0024] The loaded MAO can be heated at 40°C - 130°C for at least 1 hour or aged in the environment for at least 24 hours. It is considered that heating: 1) converts small MAO molecules soluble in non-reactive aliphatic solvents into large, insoluble reactive MAO molecules (such as the change from Figure 3 a to Figure 3 b), which can be achieved by heating at a lower temperature (e.g., 40°C - 85°C); and 2) further enhances the dimerization of MAO to make it into larger MAO molecules, which is more effective at higher temperatures (e.g., 85°C - 110°C), and this is for catalyst metal centers with high positive charges, such as catalysts from hafnium metal centers having 72 protons in the nucleus relative to catalysts from zirconium metal centers having 40 protons in the nucleus, or catalyst metal centers with open ligand frameworks; both form much tighter ion pairs, which require larger MAO anions to reduce ion pair interactions to increase activity. Therefore, heating at a higher temperature particularly significantly improves the activity of hafnium metallocene (e.g., M2) or bridged zirconocene (with an open structure to form a tighter ion pair with MAO, e.g., M3), but is not so obvious for the activity of non-bridged zirconocene (with a tight structure to form a weaker ion pair with MAO, e.g., M1).

[0025] Figure 1 is a schematic diagram showing illustrative reactive MAO formation and gelation energy curves. Figure 1It shows the contribution of the heat of formation of active MAO mainly from the reaction of water with excess TMA. Therefore, the heat of reaction is better expressed as (kcla / mol H2O). Therefore, Figure 1 the active MAO formation and MAO gelation enthalpy values in Figure 1 are estimated based on Al-CH3 + H-O-H = Al-OH + CH4, where ΔH = -41.88 (kcal / mol OH), Glaser and Sun, (2011) J. Am. Chem. Soc. [Journal of the American Chemical Society], Vol. 133(34), pp. 13323-13336, assuming it applies to MAO formation, 2Al-CH3 + H-O-H = Al-O-Al + 2CH4, where ΔH = 2x-41.88 = -83.76 (kcal / mol H2O), without considering the gelation precipitation energy and methane vaporization energy. For the active MAO (Al4O3Me6)4(AlMe3) n (n = 1), because (Al4O3Me6)4(AlMe3)1 has the formula Al1O 0.706 Me 1.588 , which is related to 0.706 (mol H2O / mol Al), so the heat of formation of active MAO is -83.76 (kcal / mol H2O) x 0.706 (mol H2O / mol Al) = -59.13 (kcal / mol Al). The MAO gel (Al3O3Me3)x has the formula Al1O1Me1, which has equal Al and O(H2O) units; thus the heat of formation is -83.76 (kcal / mol Al).

[0026] Based on the empirical formula and formation conditions of active MAO, in order to obtain a MAO structure in which each MAO molecule in the system has at least one coordinated TMA, an Al:O(TMA:water) ratio of at least 17:12 (1.42:1) and a cold reaction environment are necessary. The large heat of reaction of 59 kcal / mol water also requires an effective heat removal mechanism to maintain a low temperature environment for active MAO formation and limit the high local heat that may increase the irreversible gelation reaction to produce inactive MAO gel. To achieve this, water-rich silica in solid or slurry form can be slowly added to a dilute TMA solution cooled to the desired low temperature, such that water molecules always encounter excess TMA in a cold environment. Since TMA is always in excess, the MAO loading on silica is determined by the amount of water absorbed in the silica pores. The exact amount of water can be controlled by several methods, such as by removing an unknown amount of water originally absorbed on the raw silica via a calcination step and then accurately adding back the desired amount of water, or by analyzing the amount of water on the raw silica (such as by the LOD method) to determine whether more water should be added or removed to obtain silica with the desired water loading.

[0027] Based on the active MAO structure of (Al4O3Me6)4 which requires a stoichiometry of 16Al:12O for MAO molecules with 1 - 2 coordinated TMAs, at least 17Al:12O (TMA: water) feed can be used to form the (Al4O3Me6)4(TMA)1 active MAO structure, where the coordinated TMA acts as the active center. This structure requires a cold environment to form more effectively and become relatively stable. Thus, adding TMA to water does not effectively produce the active MAO structure because water is always in excess, and the reactive TMA will lose at least two methyl groups due to the rapid, highly exothermic reaction of TMA with water to form a more stable gel structure. There is no TMA available to form the coordinated TMA, i.e., the active center. Therefore, adding a silica - water slurry to the TMA solution is the preferred method for more effectively forming the active MAO structure because the water is always surrounded by an excess of TMA molecules to maximize the number of coordinated TMAs and thus limit the formation of the inactive MAO gel (Al:O ratio of approximately 1:1). For this reason, the water content on the silica thus determines the MAO loading, i.e., the higher the water content, the higher the MAO loading, and if the catalyst precursor requires more MAO to become fully activated, the higher the activity of the derived catalyst. However, common silicas used in many commercially loaded catalyst systems (such as Grace 948, 955, PQ ES70, and ES70X) have a surface area of slightly less than 300 m 2 / g, which limits the MAO loading. For example, a feed of approximately 8 mmol water / g silica (or 12.6 wt% water) starts to show MAO "overflow" from the pores, forming "skin"-encapsulated sMAO particles, and the activity actually decreases due to a significant surface area reduction, meaning that the pores are overfilled with MAO and clogged.

[0028] A water content of 4.3 (mmol / g silica) and the derived sMAO with approximately 6.2 (mmol TMA / g silica) can meet the activation requirements of most gas - phase LLDPE catalysts. As expected, a lower water content results in a lower MAO loading and less activity. Therefore, for silica with a surface area of approximately 300 m 2 / g or less, the useful water content range is 3.0 to 7.0 mmol / g silica. For higher water loadings, such as 5 - 6 (mmol water / g silica), the derived sMAO shows much higher activity (see Table 11 below).

[0029] For silica with a higher surface area, such as PD14024 (600 m 2 / g), even higher MAO loadings are possible which can hold more MAO to avoid formation of the "skin-wrapped" particles shown above; for example, for such silica, a 10 (mmol water / g silica)-derived MAO with a loading of about 14 mmol Al / g silica has been demonstrated (example 58 for catalyst preparation and polymerization examples Poly V and Poly VI), and the heat of reaction per gram of silica now becomes much higher so that for the same wet silica addition rate, a greater cooling capacity, e.g., -20 °C, can be used to avoid fragmentation of the formed sMAO (see sMAO formation temperature section for more details). When the catalyst is used in a sequential polymerization process to obtain, for example, a heterophasic copolymer composition such as an impact copolymer (ICP), a higher MAO loading resulting in much higher activity is very useful, and this heterophasic copolymer composition is obtained from a multi-sequential reactor device to allow the activity to drop to an operable value still when carried to the last reactor. However, the increase in surface area means that if the pore size remains the same, the silica structure is more hollow. A more hollow silica structure becomes mechanically more fragile, which is a potential source of fines that can contaminate the reactor or can cause premature polymerization fragmentation to lose the rigid pores derived from the large pores, especially harmful for sequential polymerization where the rigid pores derived from the large pores are used for rubber filling to avoid contaminating the reactor with rubber overflow. Therefore, to increase the surface area, the pore size needs to be decreased to maintain mechanical strength. However, MAO molecules cannot enter pores <50 Å; in this case, MAO cannot be formed in pores <50 Å. Therefore, the surface area cannot be increased indefinitely. To compromise between MAO loading and mechanical strength, a useful high surface area is limited to about 800 m 2 / g, and the pore size is limited to >50 Å.

[0030] A relatively accurate amount of water on the silica evenly distributed in the pores can result in a derived catalyst with good activity, operability, and polymer bulk density. "Relatively accurate" means that the water content can be in a relatively wide range, e.g., in the range of 4.3 to 5.0 (mmol water / g silica) feed, and the derived catalysts show similar operability, reactor parameter control, and derived polymer properties, but with different activities, i.e., the higher the water content, the higher the MAO loading and the higher the activity of the catalyst precursor with lower activation efficiency.

[0031] The starting silica usually contains a certain amount of adsorbed water, and this amount of adsorbed water varies with the ambient temperature and humidity. This amount is usually less than the amount for the desired MAO loading. Thus, if the amount in the starting silica can be quantified after oxygen is removed, the difference from the desired amount can be made up to obtain the desired water loading, and thus the calcination step can be eliminated. The analytical method of loss on drying (LOD) can be used to quantify the water loading of the starting silica. Another simpler method is to add the desired amount of water to the silica that has been calcined to remove the unknown amount of water. For example, the silica can be calcined under ambient N2 flow at temperatures above 150 °C (such as 200 °C, 400 °C, 600 °C, or 875 °C) to remove the adsorbed water. Different calcination temperatures result in different amounts of hydroxyl groups on the pore surface of the silica that act as anchors for TMA and MAO molecules, and thus change the ratio of the anchored MAO (supported MAO, possibly more sterically hindered and less active, based on experimental evidence) to the unanchored MAO (bulk MAO, less sterically hindered and more active, based on experimental evidence) on the support with a given MAO loading, which may lead to different activities, slurry polymerization or supercondensed mode gas-phase polymerization operability, and comonomer insertion response or composition distribution (CD) response (more details in the CD control section).

[0032] For the addition of wet silica in the form of a slurry, water can be added to the silica either before or after the slurry is formed. It is highly desirable to have water molecules uniformly distributed in the silica pores to obtain a well-distributed MAO on the support with good MAO distribution in the pores, which is directly related to the catalyst activity and the derived polymer bulk density. By XPS analysis, the Al / Si ratio of the uncrushed sMAO relative to the crushed sMAO (Al / Si(u-c)) can be used for quality control of the in-situ sMAO Al distribution. Wet silica solids heated at 55 °C for 5 hours (possibly not that long) in a closed container and wet silica slurries stirred for 2 hours in the ambient can all give an Al / Si(u-c) < 3.0, which results in the desired derived polymer bulk density. It has been found that Al / Si(u-c) is also closely related to the control of the addition of wet silica to the cold TMA solution, i.e., a narrower reaction temperature range at lower temperatures gives a smaller Al / Si(u-c) ratio. If both are carried out well, the ratio can be controlled within the range of 1 - 1.5, which is highly desirable.

[0033] As mentioned above, the water loading determines the MAO loading due to the preferred addition sequence: adding water-silica to the TMA solution. It has been observed that even when the TMA:water ratio is significantly higher than 1.4:1, the resulting sMAO has an almost constant Al:O ratio close to 1.3 - 1.4:1. In fact, because the wet silica is added slowly to the TMA solution, the initial TMA:water ratio is extremely high; only the last portion has a TMA:water ratio close to the feed ratio of TMA:water. The fixed Al:O ratio of approximately 1.4:1 matches the formula (Al4O3Me6)4 with 1 coordinated TMA (see Figure 1 , n = 1, 17Al:12O = 1.42:1). Thus, ideally, the TMA:water ratio should be controlled within the range of 1.3 - 1.5:1.

[0034] It should be understood that although a TMA:water ratio of approximately 1.4:1 can be used to form the desired active MAO molecules, the process of adding water to the TMA solution allows the feed TMA:water ratio to approach or be less than 1:1 because the first portion of wet silica added to the TMA solution is still surrounded by excess TMA and forms an active sMAO structure. Only when the TMA:water ratio is less than approximately 1.4:1 can gel molecules start to form more significantly, and the last portion of silica may not have TMA to react with it. For example, theoretically, for a 1:1 TMA:water feed ratio, 71% of the wet silica added to the TMA solution can have an environment with a TMA:water ratio of at least 1.4:1, and all of the TMA should be consumed after adding 71% of the wet silica. The remaining 29% of the wet silica should theoretically have no TMA to react with it. However, due to the equilibrium between coordinated TMA and free TMA in the TMA solution, this end point is not expected to be a clear demarcation. Instead, it is believed that when the consumption of wet silica approaches 71%, a partial gelling process occurs and then increases, and since the active MAO loading gradually decreases, the activity of the sMAO portion formed thereafter gradually decreases, as indicated by experimental observations. For example, by using silica calcined at 200 °C, as the TMA:water ratio gradually decreases from 1:5:1 to 1:30, the activity gradually decreases without a clear demarcation, and only when it is less than 1.33:1 can no free TMA be detected in the supernatant at the end of the addition. That is, by using a TMA:water feed close to 1:1, approximately 70% of the fully active loaded MAO, a portion of sMAO with gradually decreasing activity, and a portion of inactive sMAO and / or silica without MAO loading can be obtained.

[0035] Thus, by adjusting the TMA:water ratio to a lower value, such as 1.33:1 for silica calcined at 200 °C, a supernatant (solvent) free of TMA / MAO can be obtained, and this solvent can be directly reused without any treatment, which is particularly useful for designing a continuous sMAO formation process in which the solvent is recycled and reused. Another benefit is that this TMA / MAO-free supernatant process may not require filtration facilities for large-scale catalyst preparation reactor systems, thus simplifying the catalyst preparation reactor design and reducing costs.

[0036] In theory, TMA solutions of any concentration can be used, even pure TMA liquid. However, a more dilute TMA solution is beneficial for heat removal from the exothermic reaction to ensure the formation of active MAO molecules. On the other hand, if the reaction is a batch process, a more dilute solution results in lower batch production efficiency. Although a higher TMA concentration is required for higher batch production efficiency, the flammability of TMA solutions above about 12 wt% may be a safety issue in use. Another important factor in designing the TMA concentration is the final sMAO slurry concentration and the finished catalyst product slurry concentration, which are related to the reactor stirring capacity and the carrier pore volume that determines the upper limit of the slurry concentration. For example, final sMAO and finished catalyst slurry concentrations of 22 wt% - 26 wt% are in the range of balanced batch efficiency and equipment operability for common silica carriers with a pore volume of 1 - 2 cc / g. For carriers with a higher pore volume, a more dilute slurry may be desired to suit the stirring capacity of the equipment. Therefore, if the wet silica is added in solid form, the TMA solution concentration can be more dilute, while if the wet silica is added in slurry form, the TMA concentration can be more concentrated to have a more desirable batch efficiency.

[0037] As described above, a low-temperature environment can be used to allow the formation of active MAO molecules, where coordinated TMA serves as the active center and the formation of inactive MAO gels is restricted ( Figure 1 ). However, for commercial production, the actual cooling capacity should be considered. This study reveals that maintaining the reaction temperature in the range of -8 °C to -12 °C can produce in-situ sMAO with performance comparable to conventional sMAO, where the MAO loading is 6 - 7 mmol Al / g of silica, corresponding to approximately 4 to 5 mmol of water / g of silica-derived in-situ sMAO. Another factor to consider in actual operation is how quickly the reaction heat can be removed to maintain the desired low temperature. A reactor with a lower heat removal efficiency will result in a longer wet silica addition time. Therefore, the effective cooling capacity and effective mixing of wet silica and TMA can be used to provide an actual addition time range. By using silica with a higher surface area (e.g., having 600 m 2Increasing the water content (e.g., 7 - 8 mmol water / g silica as described above) of PD14024 to avoid over - filling of MAO allows for the in - situ sMAO with a higher MAO loading. A higher water content requires greater cooling capacity to remove the heat of reaction. We have demonstrated that - 20 °C is sufficient for the preparation of in - situ sMAO derived from 8 mmol water / g silica, while - 14 °C results in significant sMAO fragmentation, both from ES70 silica calcined at 875 °C.

[0038] The new MAO activation mechanism proposed based on the experimental results is simplified as follows:

[0039]

[0040] The new mechanism in Eq. 1 (Luo and Diefenbach, Conf. abst., Adv. in Polyolefins, Santa Rosa, California, 2009 and 2011; Luo, Wu and Diefenbach, U.S. Patent 9,090,720 (2015)) provides two key factors for controlling MAO during sMAO formation and single - site catalyst activation: the guidance of coordinated TMA and free TMA in order to improve the performance of the finished catalyst. The method provided herein allows for the in - situ formation of supported MAO based on the stoichiometry and conditions of active MAO formation, and how to construct a finished catalyst based on the new MAO activation mechanism and the understanding of the interaction of MAO and TMA molecules in the pores of the support, which requires the design / selection of support parameters such as surface area, pore diameter, pore volume, particle size, and control of pore - surface hydroxyl residues (e.g., by calcination or chemical modification) to obtain a highly active, operable in large - scale polymerization reactors, and catalyst compositions with controllable polymer properties.

[0041] Any inert hydrocarbon solvent can be used, such as aromatic and aliphatic solvents. More preferably, aliphatic solvents are used because the solubility of MAO in aliphatic solvents (such as isohexane) is significantly lower than its solubility in aromatic solvents (such as toluene). The aliphatic solvent with lower MAO solubility can limit the possibility of MAO leaching into the solution. If a large amount of MAO dissolved in the sMAO supernatant is not removed, it will subsequently precipitate outside the sMAO particles, resulting in uneven distribution of Al and thus low polymer density. It may also lead to an undesired high initial polymerization heat, which is a reactor fouling factor, for example, fouling by the molten polymer resin. When using aromatic solvents, a filtration / washing step can be applied to remove soluble MAO in the supernatant, and a scale inhibitor such as a continuity agent can be added. Suitable continuity agents include long-chain hydrocarbon groups, modified compounds containing one or more hydroxyl groups, such as MPS-1E, A-990 or Varonic s202 (for more details, see the continuity agent section).

[0042] Pentane, isohexane, heptane, isoPar E, isohexane-mineral oil mixture, isohexane and Hydrobrite oil mixture can be used. These solvents have no significant effect on the activity of the catalyst derived from wet silica with a lower water content (e.g., 4.3 - 5 mmol water / g silica). When using a higher boiling point (bp) solvent such as isoPar E, a high water content (e.g., 7 - 8 mmol water / g silica) results in significant sMAO fragmentation, presumably due to lower heat removal capacity. Low boiling point solvents such as pentane and isohexane can evaporate to assist in heat removal at lower temperatures. Although isobutane or propane is expected to be better for heat removal, due to their high vapor pressure at higher temperatures, for example, when heating sMAO at 85 °C (see below) to improve both activity and operability, isobutane or propane may not be as practical as C5 - C7 hydrocarbons. Although solvents with very low boiling points can be used, they are not as safe as higher boiling point solvents.

[0043] Several methods can be used to prepare wet silica solids or slurries. A convenient method is to add water to the calcined silica hydrocarbon slurry in a container, then seal the container and place it on an oscillator or roller to stir in an environment for a certain period of time, such as 2 - 48 hours, to obtain the desired uniform distribution of water in the silica reflected by the uniformly distributed MAO Al elements determined by XPS uncrushed-crushed analysis (Method I). Another method is to add the desired amount of water to the calcined silica in a well-sealed container, where the uniform distribution of water can be achieved by heating the entire container at, for example, 50 °C - 60 °C for several hours, which can be done by the silica supplier and may not increase significant costs. Then, the water-treated silica can be directly put into a reactor together with a solvent to form a slurry for immediate use (Method II).

[0044] This disclosure also relates to catalyst systems for olefin polymerization, methods for producing these catalyst systems, and polyolefins formed from these catalyst systems. Embodiments of this disclosure include methods for preparing supported aluminoxanes by contacting at least one water-absorbing support material with at least one hydrocarbyl aluminum compound in a hydrocarbon solvent, preferably in an aliphatic solvent, at a temperature from below -5 °C to -60 °C. Supported aluminoxanes are formed in situ when the hydrocarbyl aluminum compound reacts with the water absorbed on the silica.

[0045] The newly formed supported MAO (pre-sMAO) can be heat-treated to convert it into fully active sMAO, and then it can be mixed with one or more catalyst precursors, where the heating temperature depends on the desired type of catalyst precursor for polymerization. Then, any free solvent or volatiles can be removed to obtain the supported catalyst. The in-situ supported aluminoxane is capable of working with both gas-phase polymerization processes and slurry-phase polymerization processes to obtain the desired polymer properties, including molecular weight (Mw), polydispersity index (PDI), polymer density (PD), composition distribution (CD, especially broad orthogonal composition distribution (BOCD)), bulk density (BD), melt index (MI), melt index ratio (MIR). It has been unexpectedly found that when forming in-situ supported aluminoxanes, some of these polymer properties, such as BOCD, can be adjusted by regulating the silica water loading and / or the ratio of TMA to water and the heat treatment of sMAO.

[0046] When using aliphatic solvents, the supported MAO is free of aromatic solvents. The supported aluminoxane can be prepared by adding an aliphatic solution of at least one carrier material having water-absorbing properties to a hydrocarbyl aluminum aliphatic solvent solution at a temperature from about below -5 °C to about -60 °C. The concentration of the hydrocarbyl aluminum solution can range from 0.1 wt% to 40 wt%, preferably from 1.0 wt% to 20 wt%. Using aliphatic solvents instead of toluene provides a catalyst system (and polyolefin product) that has no detectable amount of aromatic hydrocarbon solvent content while maintaining similar activity to a catalyst system prepared with preformed MAO, which is only commercially available in toluene. Another advantage of using aliphatic solvents instead of toluene is that aliphatic solvents with boiling points lower than toluene (110 °C) can be used, which makes it easier to remove the aliphatic solvent from the catalyst slurry to obtain the finished catalyst solid, resulting in a smaller amount of less harmful solvent residue in the derived polyolefin product.

[0047] Accordingly, the examples provided herein demonstrate the ability to significantly reduce the cost of preparing MAO-based supported catalysts. The examples provided also eliminate the need for cooling facilities and vessels for storing or transporting solution MAO. The problem of gel formation that occurs under cooling conditions (which still alters the composition of solution MAO) is also eliminated, allowing for better catalyst production and quality control.

[0048] Eliminating aromatic hydrocarbon solvents from the catalyst system also provides a polyolefin product that has no detectable aromatic hydrocarbon solvents (preferably no detectable toluene), as determined by gas chromatography. As used herein, the term "detectable aromatic hydrocarbon solvent" means 0.1 mg / m 2 or higher as determined by gas chromatography (GPC), and "detectable toluene" means 0.1 mg / m 2 or higher as determined by GPC. The polyolefin product can be used as a plastic material for materials that are free of toluene, such as for food packaging.

[0049] Material with water - absorbing loading

[0050] The carrier material can contain from 3 mmol of water absorbed per gram of carrier material to 12 mmol of water absorbed per gram of carrier material. The amount of water absorbed is determined by adding a known amount of water to the carrier hydrocarbon slurry in a closed container and stirring to distribute the water in the pores of the carrier and / or by standard thermogravimetric analysis methods (e.g., LOD (loss on drying)) at a temperature of 300 °C for 4 hours. Most commercial carrier materials will contain a certain amount of absorbed water, and in some cases, the amount of absorbed water may be sufficient. In other cases, additional water can be added or the carrier material can be dried, and then the carrier material can be brought into contact with water. This can be achieved, for example, by slurrying silica in an aliphatic solvent (such as hexane) that contains an amount of water sufficient to provide water absorption on the silica. In at least one embodiment, the carrier material is brought into contact with from about 3 mmol of water per gram of carrier material to about 13 mmol of water per gram of carrier material.

[0051] Preferably, the carrier material is silica, alumina-silica or a derivative thereof. Other natural or synthetic inorganic or organic / polymeric materials can also be used, such as clay, synthetic graphene having functional groups (such as hydroxyl groups) on the surface, functional group-substituted polystyrene, and other materials containing surface hydroxyl groups, polar groups or other functional groups / atoms capable of interacting with water molecules. Preferably, the carrier material has an average particle size between 1 micrometer and 200 micrometers, an average pore volume between 0.5 mL / g and 3 mL / g, and a surface area between 50 m 2 / g and 800 m 2 / g, provided that for a surface area < 400 m 2 / g, the water loading is between 3 - 9 mmol / g of silica, and for a surface area from 400 - 800 m 2 / g, the water loading is between 5 - 13 mmol / g of silica, and most of the pore size distribution is not less than 50 Å, preferably less than 60%, more preferably less than 40%, and most preferably less than 20%. The carrier material can have been treated with one or more of a Bronsted acid, a Lewis acid, a salt, and / or a Lewis base. The carrier material can contain a silylating agent. The carrier material contains a hydrocarbylaluminum compound. Preferably, one or more of the carrier materials contain an electron-withdrawing atom or group, such as an F atom or a C6F5 or C6F5O group, etc. Sources of electron-withdrawing atoms or groups include, but are not limited to, inorganic, organic, and polymeric compounds containing reactive electron-withdrawing atoms or groups, and can be electrically neutral or ionic compounds, such as SiF4, (NH4)2 + [SiF6] 2- 、AlRF2、AlR2F (R = C1 - C6 hydrocarbyl), Al(OC6F5)3, B(C6F5)3, etc.

[0052] Solvent

[0053] Although any hydrocarbon solvent can be used, including aromatic and aliphatic solvents, aliphatic solvents are more preferred. Suitable aliphatic solvents are liquid at the reaction temperature. Non-limiting example solvents are acyclic alkanes having the formula C n H (n+2) where n is from 4 to 30, such as low to medium boiling point solvents isobutane, butane, isopentane, pentane, isohexane, hexane, n-heptane, n-octane, nonane, decane and their isomers, and higher boiling point solvents / oils such as isoPar E, mineral oil, Hydrobrite oil, etc., and cycloalkanes having the formula C n H n where n is from 5 to 30, such as cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, etc. Suitable aliphatic solvents also include mixtures of any of the above solvents.

[0054] Trimethylaluminum (TMA)

[0055] Trimethylaluminum (TMA) is the selected organoaluminum compound, although a portion of the TMA can be replaced by other alkylaluminums to modify the properties of the derived MAO. Useful compounds suitable for partially replacing TMA include, but are not limited to: AlRX2 or AlR2X, AlR3, or any mixture thereof, where X = F, large substituted phenoxides such as 2,6-di-tert-butylphenoxide, or electron-withdrawing group-substituted aromatic compounds such as C6F5- or C6F5O-, and R = C1-C10 hydrocarbyl, such as Me, Et, Bu, octyl, etc.

[0056] Ratio of TMA to water

[0057] The ratio of water absorbed in the supported material to the amount of organoaluminum compound can be from 1:0.95 to 1:100. Preferably, the ratio is from 1:1.5 to 1:20; more preferably, the ratio is from 1:1.5 to 10; and most preferably, the ratio is 1:1.5 to 1:3.

[0058] The alkylaluminum can be present in an amount of about 1.5 wt% to 30 wt% aluminum based on the weight of the isolated solid product. Preferably, based on the total weight of the isolated solid product, the amount of aluminum is between 5 wt% and 25 wt%, more preferably between 6 wt% and 20 wt%.

[0059] Supported activated MAO and formation conditions

[0060] Since the inactive MAO gel is the more energetically favorable MAO structure ( Figure 1), so controlling the environment for forming the supported activated alumoxane is crucial for limiting gel formation. Quantitatively water-treated silica (wet silica) is added to a cold supported MAO-forming environment, which is a TMA aliphatic solution cooled to -5 °C or lower, where the selected temperature depends on the water content on the support. The higher the water content, the lower the required cooling temperature. For example, if the TMA:water feed ratio is 1.3:1 or higher, the rate of adding wet silica with a water loading of 4 to 7 (mmol / g silica) to the cold TMA solution can be controlled such that the average temperature is about -10 °C and the maximum temperature does not exceed -8 °C, while the rate of adding wet silica with a water loading of 7 to 13 (mmol / g silica) to the cold TMA solution can be controlled such that the average temperature is about -20 °C and the maximum temperature does not exceed -18 °C to obtain an in-situ supported MAO with an activation efficiency similar to or better than that of a supported conventional MAO with a similar MAO loading.

[0061] The water-treated support remains a free-flowing solid powder because the amount of water available for catalyst preparation ranges, for example, from 5 wt% to 12 wt% for a support with a surface area of about 300 m 2 / g and a pore volume of about 1.5 mL / g, which is significantly less than the amount of water that silica can hold, e.g., >50 wt%, thus allowing the added water to remain in the pores. Many additional methods can be used, such as in the form of a wet support aliphatic solvent slurry or in the form of a wet support solid. The wet support slurry can be added in an ambient or cold environment without significantly changing the performance. For low-boiling solvents used, such as C4-C8 aliphatic solvents, cooling can be applied. The purpose of cooling is to increase the viscosity of the low-boiling solvent slurry and thus reduce the wet silica sedimentation rate during slow slurry addition.

[0062] The supported activated MAO has an Al (derived from TMA):O (derived from water) ratio of 1.3 - 1.5:1 (mol:mol), which can be formed as the main supported MAO product in an environment with a wide range of TMA:water ratios (e.g., 1.3:1 to 100:1, 50:1 to 1000:1, or higher).

[0063] During the batch reaction process, due to the slow addition of the wet support into the TMA solution, at the beginning, the TMA:water ratio is quite high. The TMA content gradually decreases as the addition of the wet support continues. Although in order to obtain most of the loaded MAO as active MAO, the TMA:water ratio can be 1.3:1 or higher, a TMA:water feed ratio less than 1.3:1 can still be used to have reasonably good activity. For example, a 1:1 ratio can theoretically react approximately 75% of the wet support with 100% TMA to form the loaded active MAO and the remaining approximately 25% of the wet support to obtain 75% of the theoretical activity of the loaded MAO formed by a 1.3 - 1.5:1 TMA:water feed ratio.

[0064] Experimental results show that due to the coordination TMA and free TMA equilibrium in the system, there is no clear demarcation for the end point where the formation of active MAO stops and the formation of gelled MAO starts, that is, when the TMA:water ratio approaches 1.3:1, active MAO and gelled MAO are formed simultaneously; and as the TMA:water ratio becomes lower and lower, the proportion of gelled MAO becomes larger and larger. Additionally, because the energetically favorable gelation process is an irreversible reaction, there cannot be 100% active MAO formation conditions. However, the conditions can be controlled such that active MAO can be formed as the main product, for example, at temperatures below -10°C, -20°C, -40°C, or -60°C, to obtain >85%, >90%, >95%, or >99% of the loaded active MAO composition in an environment with a TMA:water ratio >1.3:1 (for example, from 1.33:1 to 100:1, from 1.5:1 to 1000:1, or higher).

[0065] If the TMA:water feed ratio is significantly less than the Al:O ratio of the active MAO, for example, for the active MAO formula (Al4O3Me6)4, 1.33:1, the TMA can be completely consumed before all the wet support is added. For example, a TMA:water feed ratio of 0.9:1 can theoretically only convert approximately 68% of the wet support into the loaded active MAO, and the remaining 32% remains as unreacted wet support because there is no TMA to react with it. Similarly, due to the coordination TMA and free TMA equilibrium, a part of the loaded gelled MAO can also be formed, especially at higher cooling temperatures, for example, above -5°C. Therefore, a TMA:water feed ratio significantly less than 1.3:1 (for example, less than 1:1, less than 0.9:1, or less than 0.7:1) is not preferred.

[0066] The active MAO of the load can also be formed in a so-called continuous process, in which a constant feed of both the wet support (in the form of a slurry or in solid form) and the TMA solution can be continuously mixed in a reaction apparatus capable of effectively removing heat. The preferred TMA:water feed ratio is 1.3:1, more preferably 1.4:1, and most preferably 1.5:1, although higher or lower ratios can also be used, such as 1.2:1 to 1:1 or 1.6:1 or higher, all ratios being mol:mol.

[0067] Based on the weight of the separated solid product, the amount of Al present on the in-situ sMAO can be about 1.5 wt% to 30 wt% aluminum. Preferably, based on the total weight of the separated solid product, the amount of aluminum is between 5 wt% and 25 wt%, more preferably between 6 wt% and 15 wt%.

[0068] Heat treatment of supported MAO

[0069] After in-situ preparation, before contacting a catalyst precursor (such as a metallocene), the supported aluminoxane can be treated at a higher temperature for a certain period of time in the form of a slurry or a solid. The high-temperature treatment can be in the range of 60 °C - 200 °C, preferably 70 °C - 140 °C, and more preferably 80 °C - 120 °C.

[0070] The heating time depends on the heating temperature. For higher temperatures, e.g., 85 °C - 120 °C, the heating time can be 0.5 - 5 hours, or 1 - 3 hours, or about 2 hours; and for lower heating temperatures, e.g., 60 °C - 85 °C, the heating time can be 2 - 8 hours, 4 - 6 hours, or 5 hours. Ambient aging can also act as heating, but requires a much longer time period, e.g., about 16 hours, about 24 hours, or about 48 hours or more. All of these heating / aging processes are considered to convert the pre-loaded MAO present as a major or minor component in the loaded MAO composition into the loaded active MAO composition. Higher heating temperatures are particularly preferred for constructing catalyst systems containing catalyst precursors that contain transition metals in the lanthanide element region or later in the periodic table, which have a higher net positive charge in the nucleus, such as hafnium metallocene (e.g., M2), or any transition metal with a structurally open ligand, such as bridged zirconocene (e.g., M3), or a half-metallocene known as a constrained geometry catalyst (CGC) (e.g., dimethylsilyl(tetramethylcyclopentadienyl)(tert-butylamido)titanium dichloride), presumably increasing the MAO molecular size by enhancing the MAO dimerization process, which may require a longer heating time due to the poorer mobility of MAO molecules on the support compared to MAO molecules in solution. The heating temperature for these catalyst precursors can be 85 °C, 95 °C, 100 °C, or 120 °C, and the heating time can be 4 hours, 6 hours, 10 hours or more.

[0071] The heating process can also be carried out at high pressure, e.g., 10 psi, 100 psi, or 500 psi, or between 0 - 760 Torr, such as 500 Torr, 300 Torr, or 10 Torr, or a controlled vacuum pressure very close to zero. A high-pressure or low-pressure inert gas (e.g., N2, Ar) stream can be applied to the high-pressure or vacuum heating process.

[0072] Although the heating or aging process can always increase the amount of active MAO by converting pre-MAO into active MAO, further heating of the formed active MAO may result in three activity changes: increase, remain almost unchanged, or decrease, depending on the MAO loading and the selected catalyst precursor structure.

[0073] If the loading of MAO is sufficient to activate most of the catalyst precursors, then if the catalyst precursor contains metal centers with very high net positive charges due to lanthanide contraction, such as hafnium metallocene like M2, or any catalyst precursor with an open ligand framework, such as bridged zirconocene like M3, further heating the loaded active MAO can significantly increase the activity. This is because heating enhances the dimerization of MAO, increasing the size of the MAO molecule, thus forming a larger MAO anion, which effectively reduces the interaction of the resulting catalyst-MAO ion pair and allows the olefin monomer to easily insert into the metal center. However, for catalyst precursors with metal centers before the lanthanide elements in the periodic table (without the lanthanide contraction effect) and with a tightly structured ligand framework, such as non-bridged metallocenes like M1, heating can affect the activity differently: 1) For a MAO loading sufficient to activate most of the catalyst precursors, heating does not cause a significant change in activity because the small MAO molecules are now large enough to form the desired weak interaction ion pairs with the tight catalyst structure, and the effect of heating-enhanced MAO size increase is not very obvious; and 2) For a MAO loading just sufficient to activate most of the catalyst precursors, the activity will actually decrease due to the dimerization of MAO molecules. The dimerization of MAO molecules reduces the number of MAO molecules and leaves some catalyst molecules without MAO molecules to activate.

[0074] Therefore, the heating temperature and heating time are determined by the MAO loading and the catalyst precursor used.

[0075] After contacting a carrier material having absorbed water with a hydrocarbyl aluminum compound in an aliphatic solvent at a low temperature, the reaction mixture can also be spray-dried in a spray-drying reactor at a higher temperature to evaporate the solvent / volatile matter and form a solid product having a desired average particle size and particle size distribution. The preferred temperature range is 60 °C - 200 °C, more preferably 80 °C - 190 °C, and most preferably 90 °C - 160 °C.

[0076] Examples of catalyst compounds that can be used in conjunction with the technological development of the present invention to form a catalyst system can be found in U.S. Patent Application Publications 2018 / 0051345 and 2019 / 0127497, the entire contents of both of which are hereby incorporated by reference.

[0077] Suitable catalyst compounds comprising metallocene compounds and post-metallocene compounds having at least two leaving groups are suitable for loading on in-situ sMAO. The leaving groups can be halogens such as F, Cl, Br, alkyl groups such as methyl, ethyl, butyl, CH2C6H5, etc., alkoxy groups such as OMe, OEt, OPr, OC6H5, OC6F5, etc., and amine groups such as NMe2, NEt2, NPr2, etc. The two leaving groups can be the same or different and can be monodentate or can be bridged to form a bidentate group.

[0078] Continuity reagent

[0079] Continuity reagents include, but are not limited to, hydroxy-containing compounds modified with long-chain hydrocarbon groups of formula I:

[0080] R o X((CH2) m OH) n . (I)

[0081] Wherein R is a C4-C 30 hydrocarbon group with or without one or more heteroatom substituents; X is a heteroatom or a main group metal atom such as N or Al; o = 1, 2, and n = 1, 2 or 3, provided that o + n = the valence state of X; m = 0, 1, 2, 3, 4. Non-limiting examples are: (CH3(CH2) 16 -C(O)O)2Al(OH) (aluminum distearate, MPS-1E), CH3(CH2) 17 N(CH2CH2OH)2 (bis-2-hydroxyethyl stearylamine, AS-990), and Varonic S202 (2 molar ethoxylate of stearyl primary amine) provided by Evonik Nutrition & Care GmbH.

[0082] Examples

[0083] The embodiments discussed and described herein can be further described with the following examples. Although the following examples relate to specific embodiments, they should not be construed as limiting in any specific aspect.

[0084] In the following examples, according to one or more embodiments provided herein, examples of in-situ silica-supported MAO (in-situ sMAO) formed by the reaction of wet silica slurries or solids with trimethylaluminum (TMA) are prepared under different conditions and combined with several different types of metallocene catalysts to form different catalyst systems, which are then tested for ethylene and propylene polymerization. Catalyst activity, gas-phase and / or slurry-phase reactor operability, and comonomer and hydrogen responses are measured. The resulting polymers are also analyzed to determine the molecular weight (Mw), polydispersity index (PDI), composition (or comonomer) distribution (CD), melt index (MI), melt index ratio (MIR), polymer density (PD), and polymer resin bulk density (BD) of the polymers derived from the PE catalyst, as well as the Mw and PDI in the homopolymer PP polymer, the Mw and PDI of the components in the biphasic impact copolymer (ICP), and the rubber content in the ICP derived from the PP catalyst.

[0085] Raw materials

[0086] The catalyst preparation, polymerization procedures, and polymer characterization for each example are described below. The raw materials used for the preparation of in-situ sMAO are: silica (PQ Corporation ES70X, ES70, and PD14024; Grace Davison 948 (G948); calcined at 200 °C, 400 °C, 600 °C, and 875 °C for 4 hours, e.g., ES70X(200) means silica calcined at 200 °C for 4 hours); TMA (Aldrich and Nouryon pure TMA, used as received without further treatment); deionized water (in-house, purged with N2 for 2 hours); isohexane (iC6, in-house, purged with N2 for 2 hours and stored over 3A molecular sieves for at least 24 hours), pentane (C5, Aldrich, purged with N2 for 0.5 hours and stored over 3A molecular sieves for at least 24 hours), heptane (C7, Aldrich, purged with N2 for 2 hours and stored over 3A molecular sieves for at least 24 hours), isoPar E (high-boiling hydrocarbon solvent (boiling range 110 °C - 140 °C), in-house, purged with N2 for 2 hours and stored over 3A molecular sieves for at least 24 hours), and Hydrobrite oil (in-house, purged with a slow N2 stream for at least 2 hours while heated at 110 °C).

[0087] M1 is the metallocene bis(1-Me-3-Bu-cyclopentadienyl)ZrCl2.

[0088] M2 is the metallocene (PrCp)2HfMe2.

[0089] M3 is the metallocene Me2Si(H4-ind)2ZrCl2.

[0090] M4 is the racemic-dimethylsilyl(4-(3',5'-di-tert-butyl-4'-methoxyphenyl)-2-methylindenyl)(4-o-biphenylyl-2-hexyl-indenyl)zirconium dichloride metallocene.

[0091] M5 is the ethylenebis(indenyl))zirconium dichloride metallocene.

[0092] Method for measuring XPS Al / Si ratio

[0093] Use this measurement to analyze the XPS Al / Si uncrushed-crushed measurements of the finished catalyst or sMAO for quality control of the Al distribution in the silica pores. To measure this, analyze the uncrushed catalyst sample and the crushed catalyst sample in a PHI Quantera II X-ray photoelectron spectrometer (XPS). Crush the catalyst sample using a mortar and pestle inside a desiccator. Once the sample is installed inside the XPS, perform a full-spectrum scan of the ID elements present and then establish high-resolution multiplex scans to obtain only the target elements, which are C, O, Si, Al, Cl, and F. Calibrate the energy by matching the primary carbon 1s edge peak to 284.8 eV. Analyze three target areas of each uncrushed catalyst sample and crushed catalyst sample in this way and take the average of the resulting atomic % of each element. Obtain the Al / Si ratio of the uncrushed and crushed sMAO or finished catalyst separately, and the value of Al / Si of the uncrushed sample:Al / Si of the crushed sample can be calculated.

[0094] Catalyst preparation

[0095] The general catalyst preparation procedure includes four main steps:

[0096] 1. Prepare wet silica in the form of a slurry or solid;

[0097] 2. Form in-situ sMAO by adding the wet silica to a cold TMA solution;

[0098] 3. Heat-treat the newly formed sMAO to convert pre-sMAO into active sMAO;

[0099] 4. Mix the active sMAO with the metallocene to obtain the finished catalyst.

[0100] References I, II and III - M1, M2 and M3 on silica - supported conventional MAO

[0101] Use a commercial MAO solution to prepare M1, M2, and M3 supported catalysts to be used as references to guide the development of the in-situ sMAO formation method and the design of derivative catalysts.

[0102] Reference preparation method I of References 1 and 3

[0103] A general method for preparing zirconocene is as follows: Under an inert atmosphere, such as under dry N2, load the calcined silica into the first reaction vessel; in the second vessel, load a 30% toluene solution of MAO (Grace) based on 6.4 mmol Al / g silica and M1 diluted in toluene solution based on 40 μmol Zr / g sMAO (Reference 1) or M3 diluted in toluene solution based on 30 μmol Zr / g sMAO (Reference 2), and mix in the environment for 30 minutes to 2 hours (this depends on the batch size (the larger the batch, the longer the stirring time)). Then, slowly add the MAO metallocene mixture to the silica solid under stirring to form a slurry of about 20 wt% - 24 wt%. After thoroughly mixing for 1 - 3 hours, remove volatiles by heating at 70°C - 75°C under vacuum (e.g., 1 - 3.5 psia), optionally under the protection of a N2 stream, for a large-scale reaction, where the reactor cannot be placed in an oven, to obtain a solid finished catalyst with the desired amount (e.g., 2 wt% - 3 wt%) of solvent residue.

[0104] Reference preparation method II of Reference 2

[0105] Under an inert atmosphere, such as in dry N2, load a 30% toluene solution of MAO (Grace) based on 6.4 mmol Al / g silica and M2 diluted in toluene solution based on 40 μmol Zr / g sMAO into the reaction vessel, and mix in the environment for 30 minutes to 2 hours (this depends on the batch size (the larger the batch, the longer the stirring time)). Then, slowly add the MAO metallocene mixture to the calcined silica solid under stirring to form a slurry of about 20 wt% - 24 wt%. After thoroughly mixing for 1 - 3 hours, remove volatiles by heating at 70°C - 75°C under vacuum (e.g., 1 - 3.5 psia), optionally under the protection of a N2 stream, for a large-scale reaction, where the reactor cannot be placed in an oven, to obtain a solid finished catalyst with the desired amount (e.g., 2 wt% - 3 wt%) of solvent residue.

[0106] Examples 1 - 8

[0107] Effect of heating on in - situ sMAO for non - bridged M1 zirconocene activation

[0108] Catalyst preparation method IA (Method IA, small - scale preparation)

[0109] Major equipment: a freezer, used to cool the wet silica slurry in a container; a 600 mL Ace glass-jacketed filtration reactor, used for sMAO formation and the preparation of the finished catalyst.

[0110] Method I for forming wet silica: Prepare the wet silica slurry in an oven, where 30 g of ES70X silica (51 μm, 291 m 2 / g, 1.58 cc / g, calcined at 200 °C, supplied by PQ Corporation) is loaded into a 200 mL bottle containing 108 g of iC6 and 2.75 g of deionized water (5.1 mmol H2O / g of silica). Allow the silica slurry to oscillate on an oscillator at room temperature for 2 hours. Cool the silica slurry in a freezer set at -30 °C for about 30 minutes to reach -10 °C to -12 °C.

[0111] sMAO formation: Similarly, in an oven, 146 g of isooctane is loaded into a 600 mL Ace glass-jacketed filtration reactor equipped with a mechanical stirrer. Cool the reactor containing the solvent to below 0 °C, where the leakage of the filter cap is checked (if leaking, tighten the filter cap), and then trimethylaluminum (TMA, Aldrich) 16.3 g (7.5 mmol / g of silica) is added. Once the temperature reaches below -10 °C, the cold silica slurry is slowly added to the TMA solution using a pipette, and the addition rate is controlled to maintain the average internal reaction temperature at -10 °C and not exceed -8 °C (about 1 hour). After adding the silica slurry, raise the reaction temperature to 1 °C and hold for 30 minutes, and then raise it to ambient temperature. Samples of this sMAO slurry are taken to isolate a small portion of the solid for XPS uncrushed / crushed Al / Si ratio testing, and the result is 1.78. Based on NMR quantification, the supernatant contains 11% unreacted TMA. Before using the sMAO in the heating studies in Examples 1 - 8 below, they are aged in the environment for 3 - 4 days.

[0112] Heating of sMAO: The heating effect is the focus of this study. In this study, two in-situ sMAO samples with different MAO loadings are used, namely, 5.1 mmol of water / g of silica and 7.5 mmol of TMA / g of silica as described above, and 4.3 mmol of water / g of silica and 6.5 mmol of TMA / g of silica according to a similar procedure. The details of different heat treatment conditions are described in Examples 1 - 8 below.

[0113] Finished catalyst: By adding pure M1 non-bridged metallocene to the sMAO slurry, stirring in the environment for 2 hours, filtering off the solvent, obtaining a wet filter cake, and drying the wet filter cake to a constant weight under vacuum, all the finished catalysts are obtained.

[0114] Gas-phase ethylene polymerization: The catalysts of Examples 1-8 were run using the standard polymerization procedure Poly Ia as described in the polymerization testing section.

[0115] Example 1 : M1 on in-situ sMAO aged in ambient, without further treatment.

[0116] A small amount of sMAO slurry without further treatment was filtered and vacuum dried in ambient to determine the solid weight. 1 g of the dried sMAO solid was mixed with 5 g of iC6 and 17.5 mg of bis(1-Me-3-Bu-cyclopentadienyl)ZrCl2 metallocene (M1) (based on 40 μmol / g feed), and shaken on an oscillator for 2 hours in ambient. The catalyst was then vacuum dried in ambient to remove the solvent. The 2 L reactor salt bed gas-phase polymerization test gave 4,885 g / g cat / h relative to the conventional sMAO-M1 standard (Reference I) of 2,912 g / g cat / h.

[0117] Examples 2 - 3 : M1 on in-situ sMAO aged in ambient, with heating and additional TMA treatment.

[0118] A small amount of sMAO slurry was charged into a high-pressure tube together with 5 drops of pure TMA and heated at 85 °C for 4 hours. The slurry was filtered and dried in vacuum in ambient to obtain approximately 5 g of sMAO solid. 1.0 g of the sMAO solid and 5 g of iC6 were charged into two 20 mL vials respectively. 14.5 mg (35 μmol / g) of M1 was charged into one vial, and 24.2 mg (60 μmol / g) of M1 was charged into the other vial. Both were shaken on an oscillator for 2 hours. The solvent was removed by vacuum drying to constant weight in ambient. The 2 L reactor salt bed gas-phase polymerization tests gave 4,773 g / g cat / h and 5,124 g / g cat / h respectively relative to the conventional sMAO-M1 standard (Reference I) of 2,912 g / g cat / h.

[0119] Example 4 : M1 on in-situ sMAO solid aged in ambient, with heat treatment

[0120] 1.0 g of sMAO solid was added to a vial and heated in an oil bath at 85 °C for 4 hours without solvent. The solid was then mixed with 5 g of iC6 and 17.5 mg of M1 (40 μmol / g) and stirred for 2 hours. The resulting slurry was vacuum dried to remove the solvent to constant weight. The 2 L reactor salt bed gas-phase polymerization test gave 3,069 g / g cat / h relative to the conventional sMAO-M1 standard (Reference I) of 2,912 g / g cat / h. The polymerization results are summarized in Table 1.

[0121] Table 1. 5.1 mmol water / g and 7.5 mmol TMA / g silica with M1

[0122]

[0123]

[0124] Examples 5 - 8 : M1 on in-situ sMAO with lower MAO loading treated under different conditions

[0125] Repeat a similar procedure of catalyst preparation method 1A, but change the water loading on silica to 4.3 (mmol / g silica) and the TMA feed to 6.5 (mmol / g silica). Those polymerization results are summarized in Table 2.

[0126] Table 2. 4.3 mmol water / g and 6.5 mmol TMA / g silica with M1A

[0127]

[0128] Tables 1 and 2 show that the in-situ sMAO-derived M1 catalysts exhibit better activity when not heated, and the catalysts with higher MAO loading show significantly higher activity. However, after heating, although the catalysts with sMAO having higher MAO loading show constant high activity in some way, the in-situ sMAO with lower MAO loading shows a reduced activity matching that of the conventional sMAO-derived M1 (Reference I) with a similar MAO loading.

[0129] Examples 9 - 16 : Effect of heating on in-situ sMAO for hafocene M2 activation

[0130] Catalyst preparation method IB (Method IB, large - scale preparation)

[0131] Main equipment: 600 mL Ace glass-jacketed filtration reactor for cooling the wet silica slurry; 4 L Ace glass-jacketed filtration reactor for sMAO formation and finished catalyst preparation.

[0132] Wet silica formation method 1: The method used here is similar to that used in Examples 1 - 8, but on a larger scale. The general procedure is as follows. In an oven, 50 - 300 g of silica (e.g., ES70X, 51 μm, 291 m 2(1.58 cc / g, calcined at 200 °C, supplied by PQ Corporation) was loaded into 1 L bottles (50 g scale), or divided into three equal portions and loaded into three 1 L bottles (100 g each) (300 g scale). 180 g of C7 was loaded into each bottle (for 50 g of silica) or 360 g of C7 (for 100 g of silica), and then for the 50 g silica preparation of Examples 9 - 14, 6.48 g of deionized water (7.2 mmol H2O / g silica) was loaded, or for Examples 15 - 16, 11.7 g of deionized water (6.5 mmol H2O / g silica) was loaded into each of the three 1 L bottles each containing 100 g of silica. One or more bottles were removed from the drying oven and placed on a roller, rolled at room temperature for 2 hours (80 rpm), and then returned to the drying oven to cool to -10 °C to -12 °C in a 600 mL Ace glass-jacketed filtration reactor, and used immediately, or left in the environment overnight for sMAO preparation the next day, also cooled to -10 °C to -12 °C in a 600 mL reactor, and then added to the cold TMA solution in a 4 L reactor; neither method resulted in significant performance differences.

[0133] sMAO formation: Similarly, in the drying oven, 1,000 g of iC6 (Examples 9 - 14) or 700 g of C7 (Examples 15 - 16) was loaded into a 4 L Ace glass-jacketed filtration reactor equipped with a mechanical stirrer. The reactor containing the solvent was cooled to below 0 °C, where the leakage of the filter cap was checked (if leaking, tighten the filter cap), and then for the 50 g silica preparation of Examples 9 - 14, 49.7 g of trimethylaluminum (TMA, Aldrich) (13.8 mmol / g silica) was added, or for the 300 g silica preparation of Examples 15 - 16, 183.86 g of trimethylaluminum (8.5 mmol / g silica) was added. Once the temperature reached below -10 °C, the cold silica slurry was slowly added to the TMA solution using a pipette, and the addition rate was controlled such that for Examples 9 - 14, the average internal reaction temperature was maintained at -20 °C and did not exceed -18 °C (about 1 hour), and for Examples 15 - 16, the average internal reaction temperature was maintained at -10 °C and did not exceed -8 °C (about 3 hours). After adding the silica slurry, the reaction temperature was raised to 1 °C and held for 30 minutes, and then raised to ambient temperature.

[0134] Heating of sMAO: The heating effect is the focus of this study. For Examples 9 and 10, sMAO was heated at 40 °C for 2 hours and at 60 °C for 4 hours respectively as in the original iC6 slurry without changing the reactor. For Examples 11 and 12, the iC6 solvent of the sMAO slurry was removed by filtration, and the solid was transferred to a 500 mL Cel-Stir reactor, and 174 g of C8 was added to form a slurry, which was heated in an oil bath at 100 °C and 105 °C for 3 hours respectively. The heated slurry was filtered to remove C8, washed with 2 × 70 g of iC6, and dried overnight to obtain solid sMAO. For Examples 13 and 15, the sMAO slurry was filtered and dried under vacuum, and then placed in a beaker (for the preparation of 50 g of silica) or kept in a 4 L reactor (for the preparation of 300 g of silica), and heated at 100 °C for 4 hours in solid form. For Example 14, the sMAO slurry was filtered, and isoPar E was added to reform a slurry in the same reactor, which was heated at 100 °C for 1.5 hours. For Example 16, sMAO was heated at 85 °C for 5 hours as in the original C7 slurry without changing the reactor.

[0135] Finished catalysts: All the finished catalysts of Examples 9 - 16 were obtained by the following steps: Based on 40 μmol / g sMAO, pure Hf M2 was added to the sMAO slurry in iC6 or C7, stirred in the environment for 2 hours, filtered to remove the solvent, obtaining a wet filter cake, washed with iC6 when using C7, and the wet filter cake was dried under vacuum to constant weight.

[0136] Gas-phase ethylene polymerization: The catalysts of Examples 9 - 14 were run using the standard polymerization procedure Poly Ib as described in the polymerization test section. The catalysts of Examples 15 - 16 were run using the standard polymerization procedure Poly VI as described in the polymerization test section.

[0137] Wet silica method II: This method first forms wet silica solids and then adds a solvent to form a wet silica slurry. Examples are as follows: In a 2 L round-bottom flask, 300 g of silica was charged and sealed with a rubber septum, and 27.0 g of water was injected and mixed well, and then it was placed in an oven set at 55 °C for 5 hours. The wet silica was cooled to ambient temperature and mixed with 1,008 g of iC6, and then transferred in 3 portions to a 600 mL jacketed reactor, where the slurry was cooled to -10 °C to -12 °C, and then the in-situ sMAO formation step was carried out.

[0138] Wet silica method III: This method first forms wet silica solids and then adds a viscous hydrocarbon solvent to form a wet silica slurry that can be added in the environment.

[0139] Wet silica method IV: This method first forms wet silica solids and adds them in solid form.

[0140] Examples 9 - 16 : M2 on in-situ sMAO under different heat treatment conditions

[0141] Apply a similar procedure, but use M2 obtained under different heating conditions with 7.2 (mmol water / g silica) and 13.8 (mmol TMA / g silica). Table 3 summarizes the relevant catalyst preparation conditions and polymerization results obtained from a laboratory 2L reactor (Examples 9 - 14). Table 4 summarizes the relevant catalyst preparation conditions and polymerization results obtained from a pilot plant R122 reactor (Examples 15 - 16).

[0142] Table 3. 7.2 mmol water / g silica and 13.8 mmol TMA / g silica with M2 (Poly I) in a laboratory 2L reactor.

[0143]

[0144] *Hf loading is 40 μmol / g sMAO for all catalysts; **The preparation of this group of catalysts was carried out by different preparations based on procedure method IA

[0145] Table 4. 6.5 mmol water / g silica and 8.5 mmol TMA / g silica with M2 (Poly VI) in pilot plant R122 polymerization.

[0146]

[0147] *Hf loading is 40 μmol / g sMAO for all catalysts.

[0148] This data indicates that when heated at higher temperatures, M2 hafnium metallocene requires a much higher water loading (i.e., MAO loading), e.g., 6.5 (mmol water / g silica) and 8.5 (mmol TMA / g silica) and 100 °C (Table 4, Example 15) to match the activity of a conventional MAO-derived loaded M2 reference (Reference I) corresponding to a 4.3 (mmol H2O / g silica) MAO loading, and 7.2 (mmol water / g silica) and 9.3 (mmol TMA / g silica) and heating at 100 °C is superior in performance to the conventional MAO reference (Table 3, Example 13).

[0149] Not wishing to be bound by theory, it is considered that the different heating effects are due to the lanthanide contraction effect, which results in a much higher net positive charge at the hafnium cation center than at the zirconium cation center, and thus leads to much closer ion pairs in hafnium metallocene than in zirconium metallocene with the same anion (i.e., the MAO anion). This is because there are 72 protons in the Hf center but only 40 protons in the Zr center, and both have almost the same nuclear size. It is thought that heating dimerizes or oligomerizes the small MAO molecules to become larger, thus reducing the ion pair tightness of hafnium metallocene, while the size effect is not so obvious because, without heating, the MAO size is already large enough to weaken the interaction of zirconium metallocene ion pairs due to the much smaller positive charge at the zirconium center.

[0150] For M1, a higher MAO loading (e.g., 5.1 (mmol water / g silica)) is sufficient to fully activate M1 metallocene. After heating to dimerize the small MAO molecules to form larger MAO molecules, the reduced number of MAO molecules is still sufficient to activate M1, so the change in activity before and after heating is not very obvious. In contrast, an increased amount of M1 produces a more active catalyst (Example 3 in Table 1 compared to Example 2). However, once the MAO loading to M1 feed ratio approaches the boundary of the complete activation ratio (e.g., 4.3 (mmol water / g silica)), the reduced number of MAO molecules now leads to a decrease in activity, approaching the conventional sMAO form. This indicates that conventional sMAO has more large MAO molecules than fresh in-situ sMAO, which is supported by the evidence that M1 zirconocene, which is sensitive to the number of MAO molecules, is more active before heating due to more MAO molecules when compared to conventional sMAO with the same MAO loading. On the other hand, M2 hafnium metallocene, which is sensitive to the MAO size and is activated by fresh in-situ sMAO, has only about half the activity of the conventional sMAO form, even with a much higher MAO loading (Table 3, Example 9). However, after heating, in-situ sMAO with the same MAO loading can perform better than conventional sMAO (Table 3, Example 13).

[0151] Examples 17 - 18 : Effect of heating on in-situ sMAO used for the activation of bridged zirconocene M3

[0152] Using catalyst preparation method IB for Examples 9 - 16 to prepare the catalysts of Examples 17 - 18, where C7 is used as the solvent and 300 g of ES70X (200 °C). The water loading is 5.0 (mmol / g silica), and the TMA feed is 7.5 (mmol / g silica). The average temperature for sMAO formation is - 10 °C and does not exceed - 8 °C. After heating at 60 °C for 4 hours, the sMAO C7 slurry is sampled first to prepare the M3 catalyst (Example 17), and the remaining slurry is heated at 95 °C for another 4 hours to prepare another M3 catalyst (Example 18). The catalysts of Examples 9 - 14 and Reference 3 are run using the standard polymerization procedure Poly Ia as described in the polymerization test section. The results are listed in Table 5 together with the conventional MAO - derived analogues.

[0153] Table 5. Comparison of the activities of M3 on in - situ sMAO heated at different temperatures

[0154]

[0155]

[0156] The data in Table 5 regarding the heating treatment study of M3 shows that even if the MAO loading is about 17% higher than that of Reference 3, if the heating temperature is not high enough, in - situ sMAO only exhibits activity similar to that of conventional sMAO with a lower MAO loading (Example 17 in Table 5 vs. Reference 3); however, if the heating temperature is high enough, an activity enhancement of about 100% can be achieved (Example 18 in Table 5 vs. Reference 3).

[0157] This observation is consistent with the metallocene structure of M3, which has a dimethylsilyl group to bridge two cyclopentadienyl rings, thus opening the metal center for the insertion of larger comonomers, which is the purpose of ligand design. The open metal center now requires larger anions to reduce the metallocenium - MAO anion - pair interaction, thus allowing monomers to insert more easily. Different from the MAO molecules in the freely mobile solution state, the loaded or solidified MAO molecules may require higher energy to meet and dimerize to form larger molecules.

[0158] Examples 19 - 20 and Comparative Example 1 - Active MAO - type verification and low - temperature heating or ambient aging to convert pre - sMAO into active sMAO

[0159] For Examples 19, 21 - 22 and Comparative Example 1, the catalyst preparation method IB used for Examples 9 - 16 was employed, with the difference that the water loading and TMA feed were changed as indicated in Table 6. Example 20 also used catalyst preparation method IB, but the wet silica slurry was prepared according to Example 25 below. Examples 19 and 20 used 300 g of silica, and Comparative Example 1 used 200 g of silica. M1 metallocene was used for the four samples with 40 μmol / g sMAO feed. The sMAO slurry treatment conditions are also listed in Table 6. Samples of the sMAO supernatant were taken before and after treatment and subjected to 1 1H NMR analysis. The Comparative Example (Comparative 1) catalyst was prepared using sMAO immediately after its formation without aging or heating.

[0160] Table 6.

[0161]

[0162] Although Examples 1 - 18 showed that higher temperatures can change the activity in all directions: increase, decrease, or remain almost unchanged, depending on the metallocene structure and MAO loading used, low - temperature heating or ambient aging always increases the activity relative to directly preparing the finished catalyst without aging or heating the freshly formed sMAO, as shown by the data in Table 6.

[0163] Heating can also reduce the soluble Al - Me - containing substances in the sMAO supernatant, which shows sharp TMA peaks or both sharp TMA peaks and broad peaks similar to MAO extracted from in - situ sMAO with THF, except that no detectable AlMe2(THF)2 was found by 1 1H NMR measurement in THF - d8 + . According to the starting feed TMA:water ratio in the range of 1.3 to 1.6:1, for higher TMA:water ratios (1.5 - 1.6:1), the soluble MAO - like substances and / or TMA become significantly less, or for lower TMA:water ratios (close to 1.3 - 1.4:1), especially for silica calcined at low temperatures (e.g., 200 °C), the soluble MAO - like substances and / or TMA completely disappear.

[0164] For example, for Table 6, with a TMA:water ratio of 1.42 in Example 20, the sMAO supernatant before and after heating at 60 °C for 4 hours was in Figure 2In the H1 NMR spectrum shown, the disappearance of the TMA peak from a to b is observed. If the feed TMA:water ratio > 1.4, for example, both Example 19 and Comparative Example 1 have a TMA to water ratio of 1.5:1. The TMA remaining in the supernatant after the formation of sMAO was quantified by NMR spectroscopy, showing an amount approximately equal to 1.5 mmol / g (feed) - 1.4 mmol / g (consumed), indicating that the active sMAO has a formula where Al:O = approximately 1.4:1, consistent with the Sinn / Kaminsky active MAO formula (Al4O3Me6)4 with one coordinated TMA, i.e., 17Al:12O = 1.42:1.

[0165] If the TMA to water ratio is higher, for example, 1.5 - 1.6:1, then a portion of MAO-like material can be detected in the supernatant, although this portion is very small and significant amplification of the NMR spectrum is required to see this broad peak overlapping with the TMA peak, as Figure 3 shown in a, which is from the supernatant of Example 19 with a TMA:water ratio of 1.5. However, this MAO-like broad peak does not have detectable + material, as Figure 3 shown in b, which is from any in-situ sMAO extracted with THF and analyzed by H1 NMR in THF-d8 solvent. This material is formed by the cleavage of THF coordinated to TMA (as shown in Eq 1), which is the main MAO active center. Conventional sMAO or in-situ sMAO THF extraction shows such material, for example, for the THF extraction of the catalysts from Examples 19 - 22 listed in Table 6.

[0166] On the other hand, for a TMA:water ratio of 1.3 - 1.4:1, such as Example 21 in Table 6, after the formation of sMAO, the supernatant without any treatment shows neither TMA nor MAO-like material. This indicates that if more wet silica is added, there will be no TMA to react with it. This shows the ratio limit of TMA to water, i.e., 1.3 - 1.4:1. A lower TMA:water ratio will produce a portion of unreacted water-silica, which, when heated, can allow the unreacted water to continue reacting with the active sMAO, turning them into a gel.

[0167] A portion of the in-situ sMAO supernatant containing MAO-like material from Example 20 was mixed with ethylenebis(indenyl)zirconium dichloride (M5 highly active 1-hexene polymerization catalyst precursor), and as expected, neither activation nor activity towards 1-hexene was shown. Details are described in Example 34. This indicates that the formation of active MAO can undergo a multi-step process, including the formation of small, aliphatic-soluble inactive molecules before dimerization / oligomerization to form active MAO molecules. The heating process can help accelerate the formation of active aggregated molecules, such as the tetramer shown in Figure 1 Ambient temperature aging can also increase the activity, but requires a much longer time period, such as several days.

[0168] Another observation is that the heating process also helps reduce the THF-extractable MAO, presumably by dimerization / oligomerization of smaller, more soluble unanchored MAO molecules into larger, insoluble unanchored MAO molecules, or by dimerization / oligomerization with anchored MAO molecules to become anchored. If no heat treatment is performed to reduce solubility, it is speculated that soluble unanchored active MAO molecules would cause fouling in slurry polymerization. This observation is supported by the slurry polymerization results (Table 10).

[0169] In summary, it is believed that low-temperature heating (such as 40 °C - 60 °C) or ambient aging (e.g., 24 hours) after the formation of fresh in-situ sMAO converts pre-sMAO into active sMAO, while higher temperatures (e.g., 85 °C - 130 °C) can increase the MAO molecular size and more significantly alter the activity of size-sensitive metallocenes. Low-temperature or ambient aging treatment always increases the activity of sMAO due to the conversion of inactive MAO into active MAO, while high-temperature heating is catalyst structure-dependent and MAO loading-dependent, i.e., the activity can become higher, lower, or remain almost unchanged as the amount of MAO decreases due to dimerization / oligomerization to form larger MAO.

[0170] Example 23 and Comparative Examples 2 and 3 : Active in-situ sMAO formation temperature boundary of common silica

[0171] The catalyst preparation method IB described in Examples 9 - 16 was used in these two comparative examples. For a surface area of approximately 300 m 2Silica ES70X (200 °C) at 1 g, the useful water loading is in the range of 4 - 8 mmol water / g silica. In this study, an intermediate water loading was used, i.e., 6 mmol / g silica (9.7 wt% water), the TMA feed was 8 mmol / g silica, giving a TMA:water ratio = 1.33. 50 g of ES70X (200 °C) was used to form a silica slurry with C7. The average sMAO formation temperature was controlled at -5 °C and not exceeding -4 °C. Comparative Examples 2 and 3 were prepared using M2 metallocene, where Comparative Example 2 used sMAO without aging or heating, and Comparative Example 3 used sMAO after heating at 85 °C for 5 hours. These two catalysts were tested for gas-phase ethylene polymerization with a salt bed using the Poly Ib procedure described in the polymerization test section, and the results were compared with the results of M2 on in-situ sMAO with a similar water loading but formed at -10 °C in Table 7.

[0172] Table 7. Effect of in-situ sMAO formation temperature on the activity of M2 catalyst

[0173]

[0174] The data in Table 7 show that the most critical condition for forming active in-situ sMAO is the reaction temperature. The activities of both comparative examples are significantly lower than 1,000 g / g cat / h, which is the operable limit of the catalyst in a larger pilot or commercial unit. Based on Figure 1 , since the formation of MAO gel is much more energetically favorable, the sMAO formation temperature should be low enough to maintain the active MAO structure, thereby limiting (not eliminating) the formation of gel MAO as the main product. And based on the results in Table 6, the reaction temperature boundary for a water loading of 4 - 6 mmol / g silica should be between -5 °C and -10 °C to enable M2 to have an actual activity of >1,000 g / g cat / h. And for a water loading higher than 6 mmol / g silica, a lower reaction temperature may be required, such as -20 °C.

[0175] Another useful observation is that much experimental evidence supports that even under cooling conditions, gel MAO formation and active MAO formation always coexist, and only at lower temperatures does active MAO formation have a higher ratio. Therefore, using a TMA:water feed ratio of 1.33 that matches the active MAO formula, at lower temperatures, such as -10 °C in Example 21 in Table 6, all TMA is consumed; while at higher temperatures, such as -5 °C in this comparative example, the supernatant after MAO formation contains much more TMA because gel MAO requires a TMA:water ratio of 1:1 and forms gel molecules with less TMA, so a feed of TMA:water of 1.33:1 results in an excess of TMA in the supernatant. Therefore, it can be concluded that at -10 °C or lower, a water loading of approximately 6 mmol / g of silica can cause most of the MAO to form as active MAO, but at -5 °C, most of the MAO is gel.

[0176] Example 24 and Comparative Example 4 : Active in-situ sMAO water loading limit on common silica

[0177] In this comparative example, catalyst preparation method IA described in Examples 1 - 8 was used. Because a higher water loading was used, smaller silica ES70 (38 μm vs. ES70X 51 μm) was selected to reduce the chance of local overheating at the center of the silica particles, and the silica was calcined at a higher temperature of 875 °C to remove most of the reactive siloxy groups in the silica. At a surface area of approximately 300 m 2 / g, the useful water loading ranges from 4 - 8 mmol of water / g of silica. In this study, a water loading of 8.3 (mmol / g of silica) (12.8 wt% water) was intentionally used to anticipate MAO overfilling. A TMA feed of 13.9 (mmol / g of silica) gives a TMA:water ratio = 1.56. 10 g of ES70 (875 °C) was used to form a silica slurry with iC6. The average sMAO formation temperature was controlled at -19 °C and not exceeding -16 °C. The newly formed sMAO was heated in isoPar E at 100 °C for 3 hours and then mixed with M2 metallocene to prepare Comparative Example 4. The small sMAO sample after heating was analyzed by scanning electron microscopy (SEM) and compared with Example 52a prepared by a similar procedure but with a lower water loading. The SEM images are shown in Figure 10, respectively, a corresponds to Example 24, and b corresponds to Comparative Example 4. The catalyst was tested for gas-phase ethylene polymerization with a salt bed using the Poly Ib procedure described in the polymerization test section, and the results were compared with the results from M2 on in-situ sMAO with a lower water loading but similar heat treatment in Table 8.

[0178] Table 8. Water loading limit study on in-situ sMAO for the activity of the derived M2 catalyst

[0179]

[0180]

[0181] Figure 10 shows that the sMAO derived from 8.9 (mmol water / g silica) (or 12.8% water) has some "skin-wrapped" particles, indicating that the MAO has been overfilled and leaked to the outside of the pores, thus coating the surface of the silica particles. Although Comparative Example 4 has a MAO loading of 35 wt% compared to Example 52a with only 25 wt% MAO based on the yield relative to the weight of the feed silica, the activity of Comparative Example 4 is actually much smaller than that of Example 52a, as shown in Table 8. This is consistent with the observation of conventional MAO loading. If overfilled, the pores are blocked and the metallocene molecules cannot enter, wasting those active MAO molecules. This indicates that for most commercial silica carriers with a surface area of 300 m 2 / g or less, the water loading should not be greater than 8 mmol / g silica.

[0182] Examples 25 - 27 : Other wet silica preparation methods

[0183] 1. Wet silica can be prepared as a slurry with a low-boiling solvent (such as C5-C8) and cooled to a lower temperature (e.g., -10 °C) to increase the slurry viscosity (if necessary), and the slurry is passed through a longer distance to the main reactor to form sMAO in-situ, such as the wet silica preparation method 1 in catalyst preparation methods IA and IB used in Examples 1-24, where the silica is first mixed with the solvent to form a slurry, and then water is added and allowed to stir in the environment for 2 hours before use.

[0184] 2. Wet silica can be prepared by first adding water in a closed container using the catalyst preparation method IA or IB reactor device and placing the container in an oven to heat to a low temperature (such as 40 °C - 60 °C) to allow the water to be evenly distributed in the silica pores, and then mixing with the solvent under cooling or in the environment to form a slurry, and immediately adding it to the cold TMA solution.

[0185] Examples 20 and 25, Catalyst preparation method IC (Method IC):

[0186] Wet silica preparation method 2: For Example 20, 300 g of ES70X(200) silica was charged into a 2 L round-bottom flask, sealed with a rubber septum, and 27.0 g of water (5.0 mmol / g silica) was injected and mixed well. Then it was placed in an oven set at 55 °C for 5 hours. The wet silica was cooled to ambient temperature and mixed with 1,008 g of iC6, and then it was transferred in 3 portions to a 600 mL jacketed reactor where the slurry was cooled to -10 °C to -12 °C. For Example 25, a similar procedure was followed, but 150 g of ES70(875) silica was used with 11.61 g of water (4.3 mmol / g silica).

[0187] The formation of sMAO, the heating of sMAO, and the finished catalyst all followed the catalyst preparation method IB procedure. For Example 20, 154 g of TMA (7.1 mmol / g silica) was used, and for Example 25, 74.7 g of TMA (7.0 mmol / g silica) was used; for Example 20, the solvent iC6 was used, and for Example 25, C7 was used; for Example 20, the sMAO slurry heating temperature was 60 °C, and for Example 25, the sMAO slurry heating temperature was 85 °C; for both, M1 based on 40 μmol / g sMAO was used to prepare the finished catalyst. The yield of Example 20 was 439 g with 0.58% solvent, and the yield of Example 25 was 388 g with negligible solvent.

[0188] 3. Wet silica can be prepared into a viscous slurry by adding a viscous solvent (such as Hydrobrite oil), so that the viscous slurry can be added in the environment, and a slurry pump (such as a Lambda peristaltic pump) can be used to accurately meter the wet silica. The following Example 26 is one of the examples:

[0189] Example 26, Catalyst preparation method II (Method II)

[0190] Wet silica preparation method 3: 200 g of ES70X(200) silica and 16.9 g of deionized water (4.7 mmol / g silica) were charged into a 1 L round-bottom flask, sealed with a rubber septum and taped. Then the flask was weighed and the number was recorded. Then it was placed in an oven set at 55 °C for 5 hours. The flask was taken out of the oven and cooled to ambient temperature. The weight was recorded again and compared with the weight before entering the oven to ensure that no significant water escaped.

[0191] sMAO Formation and Heating: 43.38 g of the above-mentioned wet silica was loaded into a beaker containing 170 g of Hydrobrite oil and thoroughly mixed with a spatula. Then, the slurry was added to a 4 L jacketed filtration reactor containing 1 L of isohexane (about 660 g) and 20.2 g of TMA (6.46 mmol / g of silica) that had been cooled to -12 °C through a Lambda peristaltic pump. The addition rate was controlled such that the temperature of the reaction material did not exceed -8 °C. After adding the wet silica slurry, the reactor temperature was raised to 1 °C and held for 30 minutes, then raised to 60 °C and held for 3 hours, and then cooled to ambient temperature. The slurry was filtered and washed several times with isohexane to remove the Hydrobrite oil.

[0192] The finished catalyst follows catalyst preparation method IB, where M1 based on 40 μmol / g of sMAO is used to prepare the finished catalyst. Yield: 52.0 g.

[0193] 4. Wet silica can be added in solid form through a solid pump (such as a Lambda solid feeder) to accurately meter the wet silica. Example 27 below is one of the examples.

[0194] Example 27, Catalyst Preparation Method III (Method III)

[0195] Wet Silica Preparation Method 4 (Solid Addition): 40 g of ES70X(200) silica and 3.24 g of deionized water (4.5 mmol / g of silica) were loaded into a 250 mL round-bottom flask, sealed with a rubber septum and taped. Then the flask was weighed and the number was recorded. Then it was placed in an oven set at 55 °C for 5 hours. The flask was taken out of the oven and cooled to ambient temperature. Weighed again and compared with the weight before entering the oven to ensure that no significant water escaped.

[0196] sMAO Formation and Heating: Then the heat-treated wet silica solid was loaded into a Lambda solid feeder and added to a 4 L jacketed filtration reactor containing 800 g of isohexane and 19.2 g of TMA (6.7 mmol / g of silica) that had been cooled to -12 °C. The addition rate was controlled such that the temperature of the reaction material did not exceed -8 °C. After adding the wet silica slurry, the reactor temperature was raised to 1 °C and held for 30 minutes, then raised to 60 °C and held for 3 hours, and then cooled to ambient temperature and left overnight. Then the filtrate was filtered and dried under vacuum for 5 hours. Yield: 57 g.

[0197] Finished catalyst: Charge 1 g of sMAO from ii), 4.0 g of isohexane, and 17 mg of pure M1 (40 μmol Zr / g) into a 20 mL vial, and place the vial on an oscillator to oscillate for 2 hours in the environment. Then filter the filtrate and dry it under vacuum for 30 minutes. Yield 1.0 g.

[0198] Analyze the catalyst produced in Examples 25 - 27 by XPS Al / Si u-c Analyze the catalysts produced in Examples 25 - 27, test them with Poly Ia polymerization, and summarize the results in Table 9.

[0199] Table 9. Comparison of M1 on in - situ sMAO from different preparation methods

[0200]

[0201] Examples 15, 16, 19, 20, 28 - 59 : Adjust the catalyst activity / resin bulk density by varying the component ratio and formation conditions

[0202] Catalyst preparation methods, water loading, TMA feed, ratio of water to TMA, sMAO formation temperature, heating temperature, etc. can affect catalyst performance, including activity, polymerization reactor operability, polymer properties, especially CD and resin bulk density, etc. For example, if a higher activity is required for the catalyst system, the MAO loading (corresponding to water and TMA loadings) can be increased, but at the same time, the reaction temperature and / or the wet silica addition rate should be decreased to maintain the sMAO product with active sMAO as the main product and limit the formation of MAO gel. Calcined silica at a lower temperature can be beneficial for catalyst operability under slurry polymerization conditions, but the TMA consumption is slightly higher because there are more surface hydroxyl groups reacting with TMA. The ratio of the amount of TMA to the amount of silica can be controlled so that the TMA residue remaining in the supernatant is undetectable, which is beneficial for the catalyst production process, but the activity may be decreased due to the lack of TMA to form active sMAO at the end of the wet silica addition, resulting in a part of sMAO with much lower activity; it may be necessary to increase the MAO loading to compensate for the decrease in activity. The following examples show that the activity varies with the change of component ratio and formation conditions.

[0203] Pilot tests were conducted on the in-situ sMAO-derived M1 catalyst used in both the small gas-phase PE reactor R125 and the large gas-phase PE reactor R122 to evaluate different catalyst preparation techniques (Method 1B and Method 1C) for preparing in-situ sMAO formed under different conditions, including different water loadings, TMA:water ratios, sMAO formation temperatures, solvent effects, etc. Details of the starting materials and polymerization results are summarized in Tables 10 and 11, both from catalyst preparation Method 1B but using the Poly IV and Poly III polymerization procedures respectively. Since the catalysts obtained from Method 1B and Method 1C did not show significant differences, they can be used interchangeably and are not provided in the table below.

[0204] Table 10: Pilot R122 activity data of the M1 catalyst supported on in-situ sMAO relative to the M1 catalyst supported on conventional sMAO (Reference I) from the Poly IV polymerization test.

[0205]

[0206]

[0207] The data in Table 10 are arranged from the most recent to the earlier results, with the Reference I activity and bulk density set as the targets to be achieved, and each group separated by a double line. A gradual improvement is shown from Example 21, which gives excellent activity but significantly poor bulk density, to Examples 30 - 31, which give excellent bulk density but significantly poor activity, to Examples 28 - 29, which are close to the target activity and bulk density, to Examples 19 - 20, which give better activity and very close bulk density, which is highly desirable.

[0208] Table 11: Pilot R125 activity data of the M1 catalyst supported on in-situ sMAO relative to the M1 catalyst supported on conventional sMAO (Reference I) from the Poly III polymerization test.

[0209]

[0210]

[0211] The data in Table 11 are also arranged from the most recent to earlier results, where the reference I activity and bulk density are set as the targets to be achieved, and each group is separated by a double line. It shows a stepwise improvement from Example 42, which gives too high an activity to contaminate the reactor and very high water and TMA contents, to Examples 40 - 41, which give both excellent activity and bulk density and still significantly higher TMA (8.3 - 8.7 mmol Al / g silica) compared to reference I (6.4 mmol Al / g silica), to Examples 38 - 39, which give the target activity but poor bulk density with reduced TMA and water amounts, and to Examples 19 - 20, which give better activity and very close bulk density, which is highly desirable.

[0212] In - situ sMAO - derived bridged zirconocene M3 was tested in laboratory 2L salt - bed reactor polymerization and in pilot - scale tests in both small gas - phase PE reactor R125 and large gas - phase PE reactor R122 to evaluate the catalyst preparation from the apparatus described in (Method 1B and Method 1C), except that Example 48 is from Method III. Details of the starting materials and polymerization results are summarized in Tables 12 and 13.

[0213] Table 12. Laboratory 2L polymerization results of in - situ sMAO - derived M3

[0214]

[0215] * Example 48 was prepared by Method III

[0216] The laboratory 2L reactor polymerization data in Table 12 again show the relationship between activity and MAO loading determined by the water loading on silica: the higher the MAO loading, the higher the activity. However, when the MAO loading approaches the silica MAO loading limit, the activity reaches a limit and actually decreases, presumably due to complete filling of MAO and no longer being able to utilize the catalyst or hindering monomer entry, indicating that water loadings such as that of ES70X silica with 300 m 2 / g surface area have the highest activity limit for water loadings (e.g., about 6 - 7 mmol / g silica (Example 45)). The high activity at 6 mmol / g silica water loading (Example 45) caused fouling in pilot - scale gas - phase polymerization due to too hot polymerization resulting in resin melting. Therefore, M3 metallocene is formed with 4 - 5 mmol water / g silica, with activity under control. Table 13 below shows the small - scale and large - scale pilot results from catalysts with lower water loadings.

[0217] Table 13. Pilot - scale R125 and R122 polymerization results of in - situ sMAO - derived M3

[0218]

[0219]

[0220] *The M3 dichloride (Example 50) was compared with the dimethylide (Example 49).

[0221] The data in Table 13 show that by adjusting the ratio of TMA to water and / or using an alkylated metallocene, it is possible to achieve a higher bulk density and comparable activity (Example 51) or higher activity and a comparable bulk density (Example 49) relative to the standard.

[0222] The in-situ sMAO-derived hafnium metallocene M2 catalyst was tested in a laboratory 2L salt-bed reactor and in pilot tests in both a small gas-phase PE reactor R125 and a large gas-phase PE reactor R122 to evaluate the catalyst preparation from the apparatus described in (Method 1B or IC) to prepare in-situ sMAO formed under different conditions, including different water loadings, TMA:water ratios, sMAO formation temperatures, solvent effects, etc. Details of the starting materials and polymerization results are summarized in Tables 14 and 15. M2 is sensitive to the heating temperature and the presence of free TMA.

[0223] Table 14. Laboratory 2L polymerization results of in-situ sMAO-derived M2 relative to reference sMAO-derived M2

[0224]

[0225]

[0226] Table 15. Pilot R125 and R122 polymerization results of in-situ sMAO-derived M2

[0227]

[0228]

[0229] Again, as can be seen from Tables 14 and 15, increasing the water loading and the ratio of TMA to water generally increases the activity of M2. However, heating plays a more critical role in activity improvement (Table 14, from 55 to 52). The R125 results show that a high water loading (Example 57, 7.8 mmol / g) leads to a low bulk density and poor activity, probably because some pores are overfilled, creating dead ends for polymer growth and the lower heating temperature is not sufficient to increase the size of MAO. The optimized formulation is Example 15, where a lower water loading is used and the sMAO is heated at a much higher temperature (100 °C) to match both the activity and the bulk density to the standard target (Reference II).

[0230] Typically, based on the data in Tables 14 and 15, increasing the MAO loading does not significantly increase the activity of hafnium metallocene M2; on the contrary, heat is more effective in increasing the catalyst activity. In addition, it can be observed from Tables 10 to 15 that silica with a high to low calcination temperature can be used to obtain the desired activity, although different calcination temperatures can provide different benefits for different catalysts applied in different polymerization processes. The activity can be adjusted by changing the amount of water and the ratio of TMA to water. The TMA / water ratio is also controlled such that TMA and soluble MAO residues in the supernatant after the sMAO formation reaction are undetectable by NMR, see for example Example 31 or 21 in Table 10, where the ratio of TMA:water is about 1.3:1.

[0231] This data also shows that for more effective activation of certain catalyst systems, a high MAO loading may be required; for example, metallocenes with one or more very sterically hindered ligands (e.g., the PP metallocene M4 described in a subsequent section) generally result in low activation efficiency, which requires more MAO to activate most molecules to obtain the desired activity. Another example is changing the polymerization conditions to obtain the desired polymer properties, as in the case of HDPE, where the comonomer concentration is much lower, resulting in undesirably low activity in operation. Higher MAO loading and higher catalyst precursor loading can increase the activity to meet the desired operating activity.

[0232] Thus, it has been understood that although silica with a higher surface area can maintain a higher MAO loading without overfilling the pores, other factors should also be considered for an operable catalyst system. For example, an increase in surface area may require a decrease in pore diameter to maintain the silica wall thickness for the desired mechanical strength. However, since MAO molecules cannot enter pores with a diameter of about 50 Å or less, the decrease in pore diameter is limited. The pore space after MAO loading should be large enough for the catalyst precursor to enter and should also allow monomers (especially large comonomers) to enter freely to prevent mass transfer limitations.

[0233] Example 58 - High water loading on high surface area silica

[0234] In - situ sMAO preparation : For this preparation, catalyst preparation method IA is used, except that 20 g of silica (PD14024, 611 m 2 / g surface area, 85 mm average particle size, 1.40 cc / g pore volume, calcined at 600 °C, from PQ Corporation) and 2.88 g of water (8.0 mmol / g of silica) were combined with 72 g of iC6 to form a wet silica slurry, which was cooled to -10 °C and added to a -10 °C TMA solution (16.4 g (11.4 mmol / g of silica) with 400 g of iC6). The newly formed sMAO was heated at 60 °C for 3 hours and then cooled to ambient temperature. The solid was separated by filtration, washed with iC6, and dried overnight. Yield: 32 g.

[0235] Solid catalyst preparation : 0.0145 g of M4 (947 g / mol) was added to a 1.0 g sMAO slurry of sMAO from above and 5 g of iC6 in a 20 mL vial that had been pretreated with 0.06 g of pure TIBAL in the ambient for 30 minutes; the vial was placed on an oscillator and shaken for 2 hours; filtered and dried for 30 minutes; Yield: 1.02 g.

[0236] Catalyst slurry preparation : 19.0 g of dry mineral oil (degassed at 105 °C under N2 for 2 hours) and 1.02 g of catalyst were added to a 2 Oz top-crimped bottle to prepare a 5.0 wt% slurry.

[0237] Sequential polymerization : See Poly VI

[0238] Example 59: Polymer resin bulk density study

[0239] Resin bulk density is another important product property related to operability (e.g., particle fluidity in a gas-phase polymerization reactor) and packing volume. A higher BD is desired and is mainly achieved by two controls: the water distribution on silica and the sMAO formation conditions from the catalyst preparation section, although a good polymerization process and the use of continuous reagents in the polymerization reactor can also contribute to BD. For example, more uniformly distributed water and a smoother addition of the silica slurry with a more dilute TMA solution at a lower temperature result in a higher BD. The actual combination of these factors can allow for obtaining a product with the desired BD (i.e., a BD similar to or better than the commercial standard).

[0240] It can be understood that the water distribution can lead to a good MAO distribution in the silica pores. Therefore, when the polymer grows to replicate the structure of silica, the dead spots (without Al) that create voids (and thus reduce the packing density) will be limited. However, even with a good Al distribution, dead spots can still occur if the local heat is high enough to convert the active MAO into an inactive MAO gel. Therefore, controlling the steady addition of wet silica to the TMA solution under cooling is as important as controlling the water distribution on the silica.

[0241] XPS measurements of the uncrushed and crushed Al / Si ratios can predict the packing density before the polymerization run, which is a good QC tool for assessing the catalyst quality. A series of catalysts based on M1 metallocene on different in-situ sMAO were prepared under different conditions and tested using the polymerization procedure Poly IV in the pilot reactor R122 and the polymerization procedure Poly III in the pilot reactor R125, and the results were summarized together with the conventional sMAO standards (Reference I) in Tables 16 and 17. Figure 4 and Figure 5 in.

[0242] Table 16. Pilot R122 Results

[0243]

[0244] Table 17. Pilot R125 Results

[0245]

[0246]

[0247] Example 60 : Polymer Property Reactor Control Study

[0248] In Tables 18 and 19, the results of two representative pilot reactor runs using the M1 catalyst derived from in-situ sMAO from Example 19 and the M2 catalyst from Example 57 were compared with the results from the conventional sMAO-M1 and M2 catalysts (References I and II), respectively.

[0249] Table 18. Pilot R122 Results of M1 from In-situ sMAO (Example 19) vs. M1 from Conventional sMAO (Reference I)

[0250]

[0251] Table 18 results show that at a slightly higher MAO loading based on oxygen in MAO (from water), i.e., 5 mmol / g versus the conventional sMAO of 4.3 mmol / g, the in-situ sMAO-derived M1 exhibits a productivity approximately 14% higher over longer or shorter residence times. However, by adjusting feed controls (such as the ratios of H2 to C2 and C6 to C2, flow ratios) and inert component controls (such as N2 and iC5 composition), the desired polymer properties can be obtained that match those of the standard conventional sMAO form, such as 1.0 MI, 16 MIR, and a density of 0.918. One summary of the representative pilot R125 tests for metallocene M2 is as follows:

[0252] Table 19. Pilot R125 Results of M2 on In-Situ sMAO Versus M2 on Conventional sMAO

[0253]

[0254] Temperature = 175°F (79°C), P = 300 psig

[0255] Table 19 shows that by adjusting the ethylene (C2) concentration, H2 / C2 ratio, and comonomer (here, 1-hexene, C6) / C2 ratio, the desired MI close to 1, a polymer density of 0.92, and a desired MIR close to 26 can be obtained. Product CD also shows excellent similarity to polymers derived from conventional sMAO catalysts, as Figure 6 shown.

[0256] Examples 61 - 68 : including slurry polymerization catalysts for iPP catalyst preparation

[0257] The catalysts used in the slurry polymerization study were from Method IB, and the variations are shown in Table 20. Catalysts were prepared from calcined silica at different temperatures and under different conditions and compared under slurry polymerization conditions to study MAO leaching fouling factors. sMAO was prepared similarly to Method 1B, except that: 1) silica PD14024 (size: 85 μm; surface area: 611 m 2 / g; pore volume: 1.40 cc / g, supplied by PQ Corporation) was calcined at 600°C; 2) the water loading was 8.0 mmol water / g of silica water; 3) the TMA feed was 11.4 mmol TMA / g of silica; 4) the reaction temperature was -20°C; and 5) the sMAO slurry was treated with 5 wt% TIBAL for 30 minutes based on the sMAO weight before contacting the catalyst precursor. M4 was used as the catalyst precursor, and the feed was based on 0.16 wt% Zr. This catalyst was used to polymerize homopolymer PP (Poly V described in the polymerization test section). The polymerization results are shown in Table 20 below.

[0258] Perform slurry polymerization tests using the Poly II procedure described in the polymerization test chapter. The catalyst preparation variations and polymerization results are summarized in Table 20.

[0259] Table 20. Slurry polymerization results of M1 and M4 (Example 61) on in-situ sMAO.

[0260]

[0261] The results in Table 20 indicate that for slurry polymerization (or supercritical mode gas phase polymerization with a slurry polymerization-like environment), the catalyst requires MAO to be firmly anchored on the silica surface or aggregated into larger insoluble molecules in the pores. Several methods can be used alone or in combination to load MAO with limited MAO leaching under slurry polymerization conditions, such as using a lower calcination temperature to calcine silica, which allows more surface siloxane groups to serve as anchor points; for example, for silica with a surface area of approximately 300 m 2 / g, ES70X calcined at 200 °C has 2.2 - 2.6 mmol / g of silanol groups on silica, while ES70X calcined at 875 °C has only 0.2 - 0.4 mmol / g of silanol. Heat treatment at >85 °C (e.g., 100 °C) can force MAO to oligomerize, forming larger MAO molecules with smaller solubility. If silica calcined at a higher temperature is used, for example, to obtain the desired CD, continuity reagents such as antiscalants and / or static electron removers can be used.

[0262] Another potential fouling factor leading to MAO leaching is scavengers replacing MAO in the slurry environment. For example, TEAL and TIBAL are two popular scavengers for slurry polymerization. To avoid MAO leaching in the polymerization reactor, sMAO can be treated with scavengers at the same or a higher temperature than the target polymerization temperature, and the displaced MAO can be removed before contacting the metallocene to prepare the finished catalyst.

[0263] Yet another potential fouling factor leading to reactor fouling is neutral metallocene leaching, which is due to common incomplete activation, especially in the case of iPP catalysts, where the presence of sterically hindered ligands results in low activation efficiency. The neutral metallocene present in the system can leach out and react with scavengers (e.g., TIBAL) to form substances with low activity for homogeneous polymerization under slurry polymerization. Control of this fouling is carried out through NMR activation studies of individual metallocenes for the determined MAO:MCN ratio loaded.

[0264] Since we have shown the operability in slurry phase polymerization and gas phase polymerization. Therefore, it is expected that the derived catalyst can also be used for sequential polymerization, such as in an apparatus for ICP, where iPP is prepared in a first set of slurry reactors (e.g., slurry loop), and subsequently EP rubber is prepared in a second set of reactors (e.g., gas phase reactor).

[0265] Example 69 : CD control studies on different ratios of unanchored (solid) MAO to anchored MAO

[0266] In addition to selecting the metallocene that determines the comonomer incorporation and distribution behavior, manipulating the catalyst formation composition and conditions can also change the CD behavior. A reasonable assumption is that there are different pore depths and pore sizes in silica, which more distinguish the mobility of larger comonomers (such as 1-hexene). MAO also exists in the pores in both anchored and unanchored forms, where the unanchored MAO has a better affinity for 1-hexene due to its smaller steric hindrance relative to the anchored MAO. Without being bound by any theory, it can be schematically drawn as follows to help understanding, where the pink balls are unanchored MAO, and the blue balls are anchored MAO:

[0267]

[0268] Solid MAO (without a carrier) should have a significantly flatter CD, because compared with the polymer derived from supported MAO, the comonomer is more evenly distributed along different molecular weight fractions. The influence of solid MAO was studied by changing the ratio of solid MAO to supported MAO by mixing solid MAO with supported MAO, and supporting experimental examples were completed. Figure 7 Graphs of ethylene-hexene (C6) copolymerization derived from only solid MAO, 8 wt% solid MAO, 50 wt% solid MAO, and 0% solid MAO using M1 as the catalyst precursor are shown.

[0269] Use M1 (Example 31) on in-situ sMAO prepared by Preparation Method Ib under the conditions of Example 31 in Table 10 as the 0% solid MAO baseline. Use Tosoh (TS) solid MAO to change the ratio of solid MAO to anchored MAO.

[0270] 100% solid MAO sample: Oscillate 0.65 g of TS MAO + 5 g of C7 and 40 μmol of M1 on an oscillator for 15 minutes. Filter the resulting mixture and dry it under vacuum for 15 minutes. Yield: 0.64 g.

[0271] 50% solid MAO sample: Thoroughly mix 0.25 g of the Example 31 catalyst with 0.25 g of TS MAO M1 from a.

[0272] 8% solid MAO sample: 0.92 g of the catalyst of Example 31 was thoroughly mixed with 0.080 g of TS MAO M1 from a.

[0273] 0% solid MAO sample: Only the catalyst of Example 31.

[0274] Four catalysts were subjected to PE polymerization in a laboratory 2 L salt bed reactor using polymerization procedure Poly Ia. The polymer samples were then sent for GPC-4D analysis to obtain Figure 7 the MWD and CD shown in. From Figure 7 it can be seen that as the solid MAO increases, the CD slope becomes flatter and flatter.

[0275] The hypothesis based on Eq. 2 also indicates that the anchored MAO can be de-anchored by heating in the presence of TMA, with the expectation that TMA molecules replace the MAO molecules on the surface, as shown from b to c on the left side of Eq. 2. And the experimental results of GPC-4D composition distribution analysis of two polymer samples obtained from catalysts each using the same in-situ sMAO derived but heated in the presence of TMA (Example 2) and heated in the absence of TMA (Example 4) under similar conditions (Poly Ia) indeed show a CD difference ( Figure 8 ), that is, the polymer from the catalyst with sMAO heated in the presence of TMA shows a flatter CD, consistent with more unanchored MAO being generated.

[0276] Catalysts derived from in-situ sMAO formed by differences in conditions and differences in polymerization conditions (such as TMA: water ratio, TMA concentration, sMAO formation temperature, gas relative to slurry (or supercondensed) mode polymerization, comonomer to monomer ratio, amount of H2, etc.) may also contribute more or less to different CDs, as Figure 9 shown in, which shows the CD of the M1 catalyst on different in-situ sMAOs relative to Reference I. The CD of the polymer is closely related to the physical properties of the polymer, and it is highly desirable to have good control over manipulating the CD with good reproducibility in the preparation of catalysts for polymer production in a single gas phase reactor.

[0277] Polymerization test

[0278] Example 70 : 1-hexene polymerization for the in-situ sMAO supernatant containing MAO-like inclusions

[0279] The polymerization test of 1 - hexene was carried out using bis(indenyl)zirconium dichloride (M5) activated with the in - situ sMAO supernatant from Example 19. In a 20 mL vial, 0.015 g of M5 and one pipette of the supernatant from Example 19 were loaded and mixed well. The M5 metallocene did not show an obvious color change, indicating no activation. A thermocouple was placed in the solution, and then 0.5 mL of 1 - hexene from a pipette was added. The temperature did not increase but decreased slightly, probably due to heat carried away by the evaporation of the iC6 solvent.

[0280] Example 71, Poly Ia and Poly Ib

[0281] In the above example, the term "Poly 1" refers to a laboratory - scale 2L salt - bed gas - phase polymerization reactor, where a 2L autoclave reactor was heated to 110 °C and purged with N2 for at least 30 minutes. It was loaded with dry NaCl (350 g; Fisher, S271 - 10, dehydrated at 180 °C and subjected to a pumping / purging cycle, and finally passed through a 16 - mesh sieve before use), and MAO - or TIBAL - treated silica ((5 g), at 105 °C) and stirred for 30 minutes. The temperature was adjusted to 85 °C. At a pressure of 2 psig N2, dry and degassed 1 - hexene (2.0 mL) was added to the reactor using a syringe, and then N2 was passed into the reactor to a pressure of 20 psig. A mixture of H2 and N2 was allowed to flow into the reactor (200 SCCM; 10% H2 in N2) while stirring the bed. At a pressure of 220 psig, the catalyst shown in the above table was injected into the reactor together with ethylene. Ethylene was allowed to flow throughout the test to maintain a constant pressure in the reactor. 1 - hexene was fed to the reactor at a flow rate ratio to ethylene of 0.1 g / g. Hydrogen was fed to the reactor at a flow rate ratio to ethylene of 0.5 mg / g. The ratio of hydrogen to ethylene was measured by on - line GC analysis. After 1 hour, the polymerization was stopped by discharging the reactor, cooling it to about 23 °C and exposing the reactor to air. The salt was removed by washing twice with water. The polymer was separated by filtration, simply washed with acetone, and dried in air for at least two days. The catalyst activity is reported in the above table. It can be seen that compared with the non - spray - dried reference example, the spray - dried examples of the present invention show more than twice the catalyst activity.

[0282] Poly Ia and Poly Ib have differences in terms of starting component feed and feed ratio (Table 21):

[0283] Table 21. Initial feed and feed ratio of Poly Ia and Poly Ib components

[0284]

[0285] Example 72, Poly II

[0286] The term "Poly II" also refers to a laboratory-scale 2L slurry polymerization reactor, into which 0.16 mmol of triisobutylaluminum (TIBAL) is charged as an impurity scavenger to a 2L autoclave reactor under N2 purge. 60 ml of hexene-1 comonomer and 800 ml of isobutane diluent are added. The reactor contents are heated to 80 °C. Then, 100 mg of silica-supported catalyst is introduced into the reactor under ethylene pressure. Polymerization is initiated. The entire reactor is maintained at 325 psig. The reactor temperature is kept at 85 °C throughout the experiment. After 40 minutes, the reactor is vented and polymerization is stopped. The polyethylene resin is collected and dried.

[0287] Example 73, Poly III

[0288] The term "Poly III" refers to a small gas-phase polymerization pilot unit (R125), in which polymerization is carried out in a 7-foot-high gas-phase fluidized bed reactor with a 6-inch body and a 10-inch extension. The recycle and feed gases are fed into the reactor body through a porous distributor plate, and the reactor is controlled at 300 psi (2,068 kPa) and 70 mol% ethylene. The reactor temperature is maintained by heating the recycle gas. The supported catalyst is fed as a 10 wt% slurry in Sono Jell TM from Sonneborn (Parsippany, NJ). The slurry is thinned and transported to the reactor by feeding nitrogen and isopentane through a catalyst probe. Product is collected from the reactor as needed to maintain the desired bed weight.

[0289] Example 74, Poly IV

[0290] The term "Poly IV" refers to a larger gas-phase polymerization unit (R122) where polymerization is carried out in a 22-foot tall gas-phase fluidized bed reactor having a straight-sided section inner diameter of 13 inches and a wider tapered expansion section above. Recycle and feed gases are fed into the reactor body through a porous distributor plate, and the reactor is controlled at 290 psig and 64 mol% ethylene. The reactor temperature is controlled by manipulating the temperature of the recycle gas circuit. The catalyst is fed into the reactor in dry powder form along with an N2 carrier gas. Alternatively, the catalyst can be fed in the form of a slurry in oil along with an isopentane and nitrogen carrier stream to provide adequate dispersion in the reactor bed. A continuity additive (e.g., CA-300 from Univation) is co-fed into the reactor through a second carrier nozzle leading to the reactor bed, and the feed rate of the continuity additive is adjusted to maintain a weight concentration in the bed between 20 ppm and 40 ppm. The polymer comonomer composition is controlled by adjusting the mass feed ratio of comonomer to ethylene, and the MW of the polymer is controlled by adjusting the hydrogen concentration.

[0291] Example 75, Poly V

[0292] The term "Poly V" refers to a laboratory-scale 2L slurry polymerization reactor for homopolymerizing PP, where the reactor is heated at 107 °C with a slow N2 purge for at least 2 hours before use. The reactor is charged with 1,000 mL of propylene and 2 - 3 mL of a 3 wt% TIBAL hexane solution as a scavenger and allowed to stir for 5 minutes. The desired amount of supported catalyst mixed with mineral oil to form a 5 wt% slurry is introduced into the reactor through a 250 mL C3 push under ambient conditions and high-pressure N2. After allowing to stir for an additional 5 minutes, the reactor temperature is raised to 70 °C, and after pressurizing with high-pressure H2 in a 150 mL high-pressure vessel at ambient temperature, the desired amount of H2 is added to the reactor in an amount controlled by the pressure difference. The reaction is allowed to proceed for the desired length of time. Then the reactor temperature is lowered to ambient temperature, and the volatiles in the reactor are vented. And then the obtained polymer is dried overnight under a stream of N2.

[0293] Example 76, Poly VI

[0294] The term “Poly VI” refers to a laboratory-scale 2L slurry-gas phase polymerization for a PP-EPR copolymer (ICP), where a two-stage sequential polymerization is carried out in a 2L reactor. The first stage is a homopolymer PP polymerization similar to Poly V. The second stage involves very slowly venting the propylene pressure to reach a desired pressure, e.g., 150 psi, while maintaining the reactor between 60 °C and 70 °C. After the temperature stabilizes at 70 °C, the desired ethylene partial pressure (e.g., 180 psi), achieved by adjusting the total ethylene feed pressure equal to the desired propylene and ethylene pressure (e.g., 150 + 180 = 330 psi), is continuously introduced into the reactor. After the desired reaction time, the ethylene feed is shut off, the reactor temperature is lowered to ambient temperature, and volatiles are vented to stop the polymerization. Then the obtained ICP is dried overnight under a N2 flow. The feed of the supported M8 catalyst prepared by the procedure of A)-4) is 50 mg, and the yield of the ICP is 174 g, giving an activity of 5,520 g / g cat / h based on a 25-minute iPP polymerization and a 15-minute EPR polymerization in a 250 mL autoclave with 10 psi H2 from the environment. This gives a total Mw of 214k for the ICP product from GPC-4D (PDI = 21.7), an Mw of 284k for the iPP phase (PDI = 5.90), and an Mw of 68k for the EPR phase (PDI = 3.5), as well as approximately 36 wt% EPR and approximately 30 wt% C2 in the EPR based on HPLC-SEC analysis.

[0295] Polymer Characterization

[0296] The polymer characterizations reported above were carried out using standard procedures and techniques well established and known in the art: such as Mw and PDI molecular weight analysis, MI and MIR melt flow rate analysis, polymer density analysis, and resin bulk density analysis, with the following differences: High Performance Liquid Chromatography-Size Exclusion Chromatography (HPLC-SEC) method.

[0297] Before use, trichlorobenzene (TCB) purchased from Aldrich reagent grade was filtered through a 0.1 μm Teflon filter. The neat 1-decanol obtained from Alpha Aesar was used.

[0298] HPLC-SEC samples were prepared by placing the dried polymer in a glass vial, then the polymer characterization autosampler transferring the desired amount of 1-decanol, and heating the mixture at 160 °C while continuously shaking for approximately 1.5 hours. All amounts were measured gravimetrically. The injection concentration was from 0.1 to 2.0 mg / mL.

[0299] The automatic sampler injects 100 μL of the above-prepared sample solution into the instrument. The HPLC has a changing gradient composition of the mobile phase of 1-decanol and TCB, starting from 100 vol% of 1-decanol at a nominal flow rate of 0.025 mL / min. After sample injection, within a certain period of time, the mobile phase of the HPLC is programmed to be adjusted by changing the linear gradient from 0 vol% TCB / min to 100 vol% TCB / min. The HPLC gradient curve within the 300-minute analysis time for this analysis is 0% TCB (0 minutes), 30% TCB (150 minutes), 30% TCB (170 minutes), 50% TCB (190 minutes), 100% TCB (200 minutes), and 100% TCB (300 minutes). The sampling loop collects the HPLC eluate every 2 minutes and transfers it to the SEC. The SEC has 1,2,4-trichlorobenzene (TCB) as the mobile phase, with a nominal flow rate of 5 mL / min. The mass concentration and chemical composition of the eluate are analyzed using a polymer characterization IR5 detector.

[0300] GPC - 4D (or GPC - IR) analysis for molecular weight determination

[0301] The molecular weight distribution and moments (Mw, Mn, Mw / Mn, etc.) and comonomer content (C2, C3, C6, etc.) were determined by high-temperature gel permeation chromatography (PolymerChar GPC-IR) equipped with an infrared detector assembly (ensemble) IR5 based on a multi-channel band filter, where a broadband channel was used to measure the polymer concentration and two narrowband channels were used to characterize the composition. Three Agilent PLgel 10μm Mixed-B LS columns were used to provide polymer separation. Aldrich reagent grade 1,2,4-trichlorobenzene (TCB) with 300 ppm antioxidant butylated hydroxytoluene (BHT) was used as the mobile phase. The TCB mixture was filtered through a 0.1μm Teflon filter and degassed with an on-line degasser, and then introduced into the GPC instrument. The nominal flow rate was 1.0 mL / min and the nominal injection volume was 200 μL. The entire system including the transfer line, columns, and detector was contained in an oven maintained at 145 °C. A given amount of polymer sample was weighed and sealed in a standard vial with 80 μL of a mobile marker (heptane) added. After loading the vial into the autosampler, the polymer was automatically dissolved in the instrument by adding 8 mL of TCB solvent. The polymer was dissolved at 160 °C with continuous shaking, for most PE samples, shaking for about 1 hour or for PP samples, shaking for 2 hours. The density of TCB for concentration calculation was 1.463 g / ml at room temperature and 1.284 g / ml at 145 °C. The sample solution concentration was from 0.2 to 2.0 mg / ml, where for higher molecular weight samples, lower concentrations were used.

[0302] Using the following equation, the concentration c at each point in the chromatogram was calculated from the baseline-subtracted IR5 broadband signal I:

[0303] c = αI

[0304] where α is the mass constant determined with PE or PP standards. The mass recovery was calculated as the ratio of the integrated area of the concentration chromatogram over the elution volume to the injection mass equal to the predetermined concentration multiplied by the injection loop volume.

[0305] The molecular weight was determined by combining the universal calibration relationship with column calibration, which was performed with a series of monodisperse polystyrene (PS) standards. The MW at each elution volume was calculated using the following equation.

[0306]

[0307] where the variables with subscript "X" represent the test sample, while the variables with subscript "PS" represent PS. In this method, a PS = 0.67 and K PS= 0.000175, while a X and K X were obtained from the published literature. Specifically, for PE, a / K = 0.695 / 0.000579, and for PP, a / K = 0.705 / 0.0002288.

[0308] The comonomer composition was determined from the ratio of the IR detector intensities corresponding to the CH2 and CH3 channels, which detector intensities were calibrated with a series of PE and PP homopolymer / copolymer standards whose nominal values were pre-determined by NMR or FTIR.

[0309] The comonomer composition was determined from the ratio of the IR detector intensities corresponding to the CH2 and CH3 channels, which detector intensities were calibrated with a series of PE and PP homopolymer / copolymer standards whose nominal values were pre-determined by NMR or FTIR.

[0310] The examples provided herein demonstrated the ability to significantly reduce the cost of preparing MAO-based supported catalysts, especially if uncalcined silica was used (by determining the water uptake and compensating for the difference from the desired amount) to eliminate the calcination step, and a low-boiling solvent (such as isopentane or isobutene) was used to significantly reduce the drying time relative to dry toluene. The examples provided also eliminated the need for cooling facilities and vessels for storing or transporting solution MAO, thus saving energy. The problem of gel formation that occurs under cooling conditions (which still alters the solution MAO composition) was also eliminated, thus allowing for better catalyst production and quality control.

[0311] All patents and patent applications, test procedures (such as ASTM methods, UL methods, etc.) and other literature cited herein are hereby incorporated by reference in their entirety to the extent that such disclosure is not inconsistent with this disclosure and all permissions for such incorporation are allowed.

[0312] Certain embodiments and features have been described using a set of numerical upper limits and a set of numerical lower limits. It is to be understood that unless otherwise specified, ranges are covered that include combinations of any two values, such as combinations of any lower value with any upper value, combinations of any two lower values, and / or combinations of any two upper values. Certain lower limits, upper limits, and ranges appear in one or more of the following claims. All numerical values are "about" or "approximate" indicated values, meaning that experimental errors, machine tolerances, and other variations that would be expected by a person of ordinary skill in the art are considered.

[0313] The above also summarizes the features of several embodiments, enabling those skilled in the art to better understand this disclosure. Those skilled in the art should understand that they can easily use this disclosure as a basis to design or modify other methods or devices for performing the same purposes as the embodiments disclosed herein and / or achieving the same advantages as the embodiments disclosed herein. Those skilled in the art should also recognize that these equivalent constructs do not depart from the spirit and scope of this disclosure, and they can make various changes, substitutions, and alterations herein without departing from the spirit and scope of this disclosure, and the scope of this disclosure is determined by the appended claims.

[0314] Various terms have been defined above. In the case where a term used in a claim is not defined above, the broadest definition that has been given to that term by those skilled in the relevant art, as reflected in at least one printed publication or an issued patent, shall be given. Additionally, all patents, test procedures, and other documents cited in this application are hereby incorporated by reference in their entirety to the extent that such disclosure is not inconsistent with this application and all permissions for such incorporation are allowed.

[0315] Although the foregoing relates to embodiments of the present invention, other and additional embodiments of the present invention can be designed without departing from the basic scope of the present invention, and the scope of the present invention is determined by the appended claims.

[0316] Comparative Example 5

[0317] This example repeats Example 8 of US 5,629,253. At the start of this example, 40 g of Grace Davison 948 (G948) carrier containing 12.5 wt% water (40 g in total, 277.5 mmol water or 7.94 mmol / g silica) was added to a starting 7 °C solution of TMA (259.7 mmol) and heptane (245 mL). This comparative example uses a slightly lower water content (11.8 wt%) in the silica, and the TMA content is proportionally reduced.

[0318] The G948 silica was degassed and placed in an oven. TGA of the silica revealed a water content of 4.8 wt% (average of three measurements). The silica (45.97 g) and water (4.03 g) were combined and mixed in a capped bottle, then heated at 55 °C for 5 hours and then allowed to cool overnight. TGA indicated 11.8 wt% water (average of two measurements). The silica - water was divided into 40 samples of 1 ± 0.05 g each, with a total weight of 40.3 g; the total water amount was 264.1 mmol, and the total silanol count was estimated to be 71.1 mmol.

[0319] In a drying oven, a 1 L three-necked flask was equipped with a mechanical stirrer and a thermocouple inserted into the solution and cooled in a 7 °C bath. TMA (17.67 g, 245.4 mmol) and heptane (245 mL) were added to the flask and stirred. The 1 HNMR of the solution was obtained.

[0320] After the solution temperature stabilized, 1 g portions of silica-water were added every 2 minutes until 5 g were added. The reaction was exothermic and the temperature rose to about 13 °C. Stirring was then stopped and a small amount of solution sample (about 0.1 mL) was removed and analyzed by 1 HNMR. While stirring was stopped, the mixture was cooled to about 5 °C. Stirring was then continued and the procedure was repeated until all of the silica-water had been added. A total of 8 samples were taken for 1 H NMR in addition to the initial sample.

[0321] Analysis of the NMR data revealed that each gram of silica-water reacted with 6.92 mmol of TMA and all of the TMA was consumed by 35.6 g of silica-water. The average amount of TMA reacting with water OH plus surface SiOH (estimated to be 2 mmol / g for this ~300 m 2 / g silica) was 0.46 ± 0.04 mmol / mmol. Neglecting surface silanols, the average amount of TMA reacting with water was 1.03 ± 0.09 mmol / mmol. This indicates that the MAO form formed in this preparation was essentially gel MAO, at least mostly gel MAO (see Figure 1 ).

[0322] A solution of (1,3-Me,Bu-Cp)2ZrCl2 (M1, 0.9 g, 2.08 mmol) and heptane (20 mL) was added to the stirred cold slurry. The mixture was then heated to 74 °C with stirring for 1 hour. Stirring and heating were stopped and most of the solvent was removed while N2 was bubbled onto the surface of the mixture. After obtaining a thick but flowable mixture, it was transferred to a sintered column and N2 was passed through the sinter and the material was dried to give a free-flowing yellow solid. Yield = 48.74 g.

[0323] The polymerization test of this comparative example using the POLY Ia polymerization procedure gave an activity of 579 g / g cat / h, whereas the same metallocene M1 with a much lower MAO loading (based on 5.1 mmol water / g silica) of formula Al:O = 1.4:1 in Example 1 in Table 1 gave an activity of 4,885 g / g cat / h.

[0324] Table 22. Reaction of TMA with silica-water in Comparison 5.

[0325]

Claims

1. A method for forming a supported MAO composition, the method comprising: Forming water-bearing silica, for silica with a surface area in the range of 100 - 300 m 2 / g, the water loading is 3 - 7 (mmol water / g silica), or for silica with a surface area in the range of 400 - 800 m 2 / g, the water loading is 5 - 13 (mmol water / g silica), provided that at least 60% of the pores in the silica have a diameter of at least 60 Å or greater, and the total pore volume is in the range of 0.9 - 3 mL / g; treating the silica hydrate in solid or slurry form in a closed container at 40 °C to 100 °C for at least 10 minutes, or treating the silica hydrate in a closed or open container at 0 °C to 40 °C for at least 30 minutes; contacting the silica hydrate in solid or slurry form with a mono- or polyalkylaluminum solution, the solution comprising at least 50 mol% TMA based on total Al, the solution being cooled to a temperature in the range of -5 °C to -60 °C, provided that for a water loading of 3 - 7 mmol / g, the temperature is -5 °C or lower, and for a water loading above 7 mmol / g, the temperature is -10 °C or lower, and further provided that at least 60% of the supported MAO is formed in an environment where the TMA:water ratio is 1:0.75 or higher; and heating the supported MAO at 40 °C - 130 °C for at least 1 hour or aging it in ambient conditions for at least 24 hours.

2. The method according to claim 1, wherein For a derived catalyst system for a slurry polymerization process, the silica is uncalcined or calcined at a temperature of 600 °C or lower.

3. A catalyst system formed by contacting at least one transition metal catalyst precursor with the supported MAO formed as claimed in claim 1.

4. The catalyst system according to claim 3, wherein Heating the supported MAO at 70 °C - 130 °C for 2 - 16 hours and then contacting it with one or more transition metal catalyst precursors, the transition metal catalyst precursors comprising at least one transition metal with an atomic number > 54.

5. The catalyst system according to claim 4, wherein, The transition metal catalyst precursors comprise lanthanide elements, hafnium, tantalum, or tungsten compounds.

6. The catalyst system according to claim 4, wherein The silica is uncalcined or calcined in the range of 100 °C - 1,000 °C, and wherein the catalyst system further comprises a continuity reagent used in slurry phase polymerization or gas phase polymerization, wherein the continuity reagent is premixed with the catalyst or loaded into the polymerization reactor separately.

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