CROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial

No. 61/289,759, filed December 23, 2009, the disclosure of which is incorporated by reference in its entirety.

FIELD OF THE INVENTION

[0002] Disclosed herein are methods for producing polymerization catalyst systems.

More specifically, embodiments disclosed herein relate generally to methods for producing catalyst systems comprising a supported alumoxane, such as methylalumoxane.

BACKGROUND

[0003] One of the drawbacks of current commercial and developmental catalyst systems is the high cost. One method to reduce the overall catalyst cost for a polymerization process is to develop catalyst systems with substantially improved productivity while maintaining catalyst raw materials and manufacture costs at relatively the same levels.

[0004] One current method for preparing polymerization catalysts involves pre-mixing a methylalumoxane (MAO) solution (30 wt% in toluene) with a metallocene and supporting the resulting catalyst solution on pre-dehydrated silica. Past research and development efforts indicated that the catalyst can be made by the sequential addition of MAO on dehydrated silica followed by the addition of the metallocene or by separately making and isolating S-MAO (Silica supported MAO), slurrying the S-MAO in toluene, and then adding the metallocene.

[0005] Even though the preparation methods described above produce active catalyst, they have no advantage over the standard method of preparation. In fact, they have some draw backs in terms of catalyst activity and especially in terms of polymerization reactor fouling characteristics.

[0006] Many supported activators are described in various patents and publications which include: U.S. Patent No. 5,728,855 directed to the forming a supported oligomeric alkylaluminoxane formed by treating a trialkylaluminum with carbon dioxide prior to hydrolysis; U.S. Patent No. 5,831, 109 and 5,777, 143 discusses a supported methylalumoxane made using a non-hydrolytic process; U.S. Patent No. 5,731,451 relates to a process for making a supported alumoxane by oxygenation with a trialkylsiloxy moiety; U.S. Patent No. 5,856,255 discusses forming a supported auxiliary catalyst (alumoxane or organoboron compound) at elevated temperatures and pressures; U.S. Patent No. 5,739,368 discusses a process of heat treating alumoxane and placing it on a support; EP-A-0 545 152 relates to adding a metallocene to a supported alumoxane and adding more methylalumoxane; U.S. Patent Nos. 5,756,416 and 6,028, 151 discuss a catalyst composition of a alumoxane impregnated support and a metallocene and a bulky aluminum alkyl and methylalumoxane; EP-B l-0 662 979 discusses the use of a metallocene with a catalyst support of silica reacted with alumoxane; PCT WO 96/16092 relates to a heated support treated with alumoxane and washing to remove unfixed alumoxane; U.S. Patent Nos. 4,912,075, 4,937,301, 5,008,228, 5,086,025, 5, 147,949, 4,871,705, 5,229,478, 4,935,397, 4,937,217 and 5,057,475, and PCT WO 94/26793 are all directed to adding a metallocene to a supported activator; U.S. Patent No. 5,902,766 relates to a supported activator having a specified distribution of alumoxane on the silica particles; U.S. Patent No. 5,468,702 relates to aging a supported activator and adding a metallocene; U.S. Patent No. 5,968,864 discusses treating a solid with alumoxane and introducing a metallocene; EP 0 747 430 Al relates to a process using a metallocene on a supported methylalumoxane and trimethylaluminum; EP 0 969 019 Al discusses the use of a metallocene and a supported activator; EP-B2-0 170 059 relates to a polymerization process using a metallocene and an organo-aluminuim compound, which is formed by reacting aluminum trialkyl with a water containing support; U.S. Patent No. 5,212,232 discusses the use of a supported alumoxane and a metallocene for producing styrene based polymers; U.S. Patent No. 5,026,797 discusses a polymerization process using a solid component of a zirconium compound and a water-insoluble porous inorganic oxide preliminarily treated with alumoxane; U.S. Patent No. 5,910,463 relates to a process for preparing a catalyst support by combining a dehydrated support material, an alumoxane and a polyfunctional organic crosslinker; U.S. Patent Nos. 5,332,706, 5,473,028, 5,602,067 and 5,420,220 discusses a process for making a supported activator where the volume of alumoxane solution is less than the pore volume of the support material; WO 98/02246 discusses silica treated with a solution containing a source of aluminum and a metallocene; WO 99/03580 relates to the use of a supported alumoxane and a metallocene; EP-Al-0 953 581 discloses a heterogeneous catalytic system of a supported alumoxane and a metallocene; U.S. Patent No. 5,015,749 discusses a process for preparing a polyhydrocarbyl-alumoxane using a porous organic or inorganic imbiber material; U.S. Patent Nos. 5,446,001 and 5,534,474 relates to a process for preparing one or more alkylaluminoxanes immobilized on a solid, particulate inert support; and EP-Al-0 819 706 relates to a process for preparing a solid silica treated with alumoxane. Also, the following articles disclose supported activators and methods for their preparation: W. Kaminsky, et al, "Polymerization of Styrene with Supported Half-Sandwich Complexes", Journal of Polymer Science Vol. 37, 2959-2968 (1999) describes a process of adsorbing a methylalumoxane to a support followed by the adsorption of a metallocene; Junting Xu, et al "Characterization of isotactic polypropylene prepared with dimethylsilyl bis(l- indenyl)zirconium dichloride supported on methylaluminoxane pretreated silica", European Polymer Journal 35 (1999) 1289-1294, discusses the use of silica treated with methylalumoxane and a metallocene; Stephen O'Brien, et al, "EXAFS analysis of a chiral alkene polymerization catalyst incorporated in the mesoporous silicate MCM-41" Chem. Commun. 1905-1906 (1997) discloses an immobilized alumoxane on a modified mesoporous silica; and F.Bonini, et al, "Propylene Polymerization through Supported Metallocene/MAO Catalysts: Kinetic Analysis and Modeling" Journal of Polymer Science, Vol. 33 2393-2402 (1995) discusses using a methylalumoxane supported silica with a metallocene. Any of the methods discussed in these references are useful for producing the supported activator component utilized in the catalyst composition of the present disclosure. U.S. Patent Nos. 5,468,702 and 5,602,217 disclose aging of an activator prior to use.

[0007] U.S. Patent Application No. 09/191,922, filed November 13, 1998 describes the reaction of a Lewis base-containing support with a Lewis acidic activator to form a support bonded Lewis acid compound. The Lewis base hydroxyl groups of silica are exemplary of metal/metalloid oxides where this method of bonding to a support occurs.

[0008] Other methods of supporting an activator are described in U.S. Patent No.

5,427,991, where supported non-coordinating anions derived from trisperfluorophenyl boron are described; U.S. Patent No. 5,643,847 discusses the reaction of Group 13 Lewis acid compounds with metal oxides such as silica and illustrates the reaction of trisperfluorophenyl boron with silanol groups (the hydroxyl groups of silicon) resulting in bound anions capable of protonating transition metal organometallic catalyst compounds to form catalytically active cations counterbalanced by the bound anions; immobilized Group IIIA Lewis acid catalysts suitable for carbocationic polymerizations are described in U.S. Patent No. 5,288,677; and James C.W. Chien, Jour. Poly. Sci.: Pt A: Poly. Chem, Vol. 29, 1603 - 1607 (1991), describes the olefin polymerization utility of methylalumoxane (MAO) reacted with silica (S1O ₂ ) and metallocenes and describes a covalent bonding of the aluminum atom to the silica through an oxygen atom in the surface hydroxyl groups of the silica.

[0009] Accordingly, there exists a continuing need for developments in methods of producing polymerization catalyst systems.

SUMMARY [0010] In one aspect, embodiments disclosed herein relate to a process to prepare a polymerization catalyst composition, including: contacting an alumoxane with a support material in the presence of a solvent to form a supported alumoxane; separating the supported alumoxane from the solvent at a temperature of 80°C or less to recover a dried supported alumoxane; heat treating the dried supported alumoxane at a temperature 85°C or greater to form a heat treated supported alumoxane; and combining the heat treated supported alumoxane with a polymerization catalyst compound to form a polymerization catalyst composition.

[0011] In another aspect, embodiments disclosed herein relate to a process to prepare a polymerization catalyst composition, including: contacting alumoxane with a support material in the presence of a solvent to form a supported alumoxane; heat treating the supported alumoxane at a temperature 85°C or greater to form a heat treated supported alumoxane; separating the solvent from the heat treated supported alumoxane at a temperature of 80°C or less to recover a dried heat treated supported alumoxane; and combining the dried heat treated supported alumoxane with a polymerization catalyst compound to form a polymerization catalyst composition.

[0012] Other aspects and advantages of the invention will be apparent from the following description and the appended claims

DETAILED DESCRIPTION

[0013] Embodiments disclosed herein relate generally to methods for producing polymerization catalyst systems, more specifically, to methods for producing catalyst systems comprising a supported alumoxane, such as methylalumoxane.

[0014] The catalyst systems disclosed herein include alumoxane and a support material or carrier. For example, in the catalyst compositions disclosed herein, the alumoxane is supported by the support material or carrier, where "supported" is defined herein as being deposited on, contacted with, vaporized with, bonded to, or incorporated within, adsorbed or absorbed in, or on, a support or carrier.

[0015] Catalyst systems disclosed herein may be prepared by contacting one or more support materials with an alumoxane to form a supported alumoxane. The supported alumoxane is then heat treated, before or after isolating the supported alumoxane from the contact medium, such as a solvent facilitating the admixture of the support material and the alumoxane. The resulting heat treated supported alumoxane may then be combined with a polymerization catalyst compound to form a polymerization catalyst composition. [0016] It was unexpectedly found that by heat treating the supported alumoxane, such as a supported methylalumoxane, before or after isolating it but prior to depositing a catalyst compound, such as a metallocene, the activity of the resulting catalyst was substantially increased. Not to be bound by any theories, it is believed that the heat treatment of the supported alumoxane, such as supported methylalumoxane, results in removal of free and bound impurites, such as trimethyl aluminum, present in the alumoxane that are known to affect catalyst productivity and reactor continuity negatively. For example, methylalumoxane (MAO) as a raw material typically includes some trimethyl aluminum (TMA). It is difficult to remove the free TMA from the MAO solution as a raw material because, upon heating, the MAO / TMA mixture becomes unstable and loses its effectiveness as a catalyst component. By depositing the MAO/TMA mixture on a support, however, heat treatment may react (anchor) the MAO with hydroxy moieties of the support, and thus stabilizes the MAO. Free and some bound TMA may thus be removed safely during the heat treatment.

[0017] Heat treatment of the supported alumoxane may be conducted by heating the supported alumoxane to a temperature of at least 85°C. In other embodiments, heat treatment may be conducted by heating the supported alumoxane to a temperature of at least 90°C; or at least 100°C; or at least 120°C; or at least 130°C. In some embodiments, the supported alumoxane is heated to a temperature in the range from about 85°C to about 150°C; or in the range from about 90°C to about 130°C; or in the range from about 95°C to about 125°C; or in the range from about 100°C to about 120°C. In other embodiments, the supported alumoxane is heated to a temperature with a lower limit of at least 90°C, 95°C, 100°C, 105°C, 1 10°C, 115°C, 120°C, 125°C, 130°C and an upper limit of less than or equal to 150°C, 145°C, 140°C, 135°C, 130°C, 125C, 120°C, where the ranges are bounded by any lower and upper limit described above. The heat treatment may be conducted by maintaining the supported alumoxane at a temperature within the selected heat treatment temperature range for a time period in the range from 1 minute to 24 hours; or in the range from 30 minutes to 20 hours; or from 1 hour to 16 hours; or from 1.5 hours to 12 hours; or from 2 hours to 8 hours.

[0018] As mentioned above, the alumoxane and support material may be contacted in the presence of a solvent. The liquid solvent is typically an alkane, such as a C5 to C ₁₀ alkane, preferably a C5 to Cs alkane. Cyclic alkanes such as cyclohexane and aromatic compounds such as toluene may also be used. In addition, mineral oil may be used as a solvent. Useful solvents include ether, toluene, xylene, benzene, methylene chloride, pentane, hexane, and heptane. Such solvents should be readily removable from the supported alumoxane or heat treated supported alumoxane at temperatures of less than 80°C and under at least a partial vacuum and/or a nitrogen sweep.

[0019] The heat treatment of the alumoxane may be conducted prior to or following isolation of the supported alumoxane. For example, following formation of a supported alumoxane in the presence of a solvent, the heat treatment may be conducted prior to separation of the supported alumoxane from the solvent. When in the presence of a solvent, the heat treatment may be conducted at elevated pressures, depending upon the particular solvent and heat treatment temperature selected. The heat treated supported alumoxane may then be separated from the solvent using any number of techniques, such as evaporation, spray drying, and other methods as known to one skilled in the art, to recover a dried, heat treated supported alumoxane.

[0020] As another example, the heat treatment may be conducted following separation of the supported alumoxane from the solvent. The supported alumoxane may be separated from the solvent using any number of techniques, such as evaporation, spray drying, and other methods as known to one skilled in the art, to recover a dried supported alumoxane, where the removal of the solvent is conducted at temperatures of 80°C or less and under at least a partial vacuum and/or a nitrogen sweep. The dried supported alumoxane may then be heat treated at elevated temperatures as described above to result in the heat treated supported alumoxane.

[0021] In some embodiments, the dried supported alumoxane may be slurried in mineral oil, for example, and then heat treated at elevated temperatures as described above to result in the heat treated supported alumoxane in the form of a mineral oil slurry.

[0022] The heat treated supported alumoxane may then be combined with a polymerization catalyst compound, such as one or more metallocene catalyst compounds or transition metal catalyst compounds, to form a polymerization catalyst composition according to embodiments disclosed herein.

[0023] Additional steps may also be used in forming the catalyst compositions disclosed herein. For example, catalyst compound preparation, solution washing, drying, support material dehydration, slurry formation, and other steps typically performed when preparing catalysts may also be conducted prior to contacting the support material and the alumoxane, prior to heat treatment of the supported alumoxane, or following contact of the heat treated supported alumoxane with the catalyst compound(s).

[0024] In some embodiments, the polymerization catalyst compositions formed as described above may be further processed, such as to remove a solvent used to facilitate contacting or washing of the catalyst compound and the heat treated supported alumoxane, or to recover the catalyst composition in a dried state or as a solid. In other embodiments, the catalyst composition may be in a substantially dry state or as a slurry, such as a mineral oil slurry.

[0025] As described above, catalyst compositions according to embodiments disclosed herein may include alumoxanes, support materials, and catalyst compounds, among other components commonly used in polymerization reaction systems. The catalyst compositions may be used in various polymerization reaction systems to produce a wide variety of polymers.

Alumoxane

[0026] Alumoxanes are catalyst activators used in the polymerization catalyst compositions disclosed herein. Alumoxanes are generally oligomeric compounds containing - Al(R)-0- subunits, where R is an alkyl group. Examples of alumoxanes include methylalumoxane (MAO), modified methylalumoxane (MMAO), ethylalumoxane and isobutylalumoxane. Alumoxanes may be produced by the hydrolysis of the respective trialkylaluminum compound. MMAO may be produced by the hydrolysis of trimethylaluminum and a higher trialkylaluminum such as triisobutylaluminum. MMAO's are generally more soluble in aliphatic solvents and more stable during storage.

[0027] There are a variety of methods for preparing alumoxane and modified alumoxanes, non-limiting examples of which are described in U.S. Patent No. 4,665,208, 4,952,540, 5,091,352, 5,206, 199, 5,204,419, 4,874,734, 4,924,018, 4,908,463, 4,968,827, 5,308,815, 5,329,032, 5,248,801, 5,235,081, 5, 157,137, 5,103,031, 5,391,793, 5,391,529, 5,693,838, 5,731,253, 5,731,451, 5,744,656, 5,847, 177, 5,854, 166, 5,856,256 and 5,939,346 and European publications EP-A-0 561 476, EP-Bl-0 279 586, EP-A-0 594-218 and EP-Bl-0 586 665, and PCT publications WO 94/10180 and WO 99/15534. Another useful alumoxane is a modified methyl alumoxane (MMAO) cocatalyst type 3A, which is commercially available from Akzo Chemicals, Inc. under the trade name Modified Methylalumoxane type 3A. Another useful MMAO is described in U.S. Patent No. 5,041,584.

Support Material

[0028] The support material is any of the conventional support materials, and may include inorganic or organic support materials. Preferably the supported material is a porous support material, for example, talc, inorganic oxides and inorganic chlorides. Other support materials include resinous support materials such as polystyrene, functionalized or crosslinked organic supports, such as polystyrene divinyl benzene polyolefins or polymeric compounds, zeolites, clays, or any other organic or inorganic support material and the like, or mixtures thereof.

[0029] The preferred support materials are inorganic oxides that include Group 2, 3, 4, 5,

13 or 14 metal oxides. The preferred supports include silica, which may or may not be dehydrated, fumed silica, alumina (WO 99/60033), silica-alumina and mixtures thereof. Other useful supports include magnesia, titania, zirconia, magnesium chloride (U.S. Patent No. 5,965,477), montmorillonite (European Patent EP-B1 0 51 1 665), phyllosilicate, zeolites, talc, clays (U.S. Patent No. 6,034, 187) and the like. Also, combinations of these support materials may be used, for example, silica-chromium, silica-alumina, silica-titania and the like. Additional support materials may include those porous acrylic polymers described in EP 0 767 184 B l. Other support materials include nanocomposites as described in PCT WO 99/47598, aerogels as described in WO 99/48605, spherulites as described in U.S. Patent No. 5,972,510 and polymeric beads as described in WO 99/5031 1.

[0030] The support material may have a surface area in the range of from about 10 to about 700 m ² /g, or in the range of from about 50 to about 1000 m ² /g, or in the range is from about 100 to about 400 m ² /g, or in the range of about 200 to about 600 m ² /g, or in the range of about 245 to about 375 m ² /g, or in the range of 410 to about 620 m ² /g, or in the range of about 390 to about 590 m ² /g.

[0031] The support material may have a pore volume in the range of from about 0.1 to about 4.0 cc/g, or from about 0.5 to about 3.5 cc/g, or from about 0.8 to about 3.0 cc/g. In some embodiments, the support material may have a pore volume in the range of from 0.5 to about 6.0 cc/g, or from about 1.1 to about 1.8 cc/g, or from about 2.4 to about 3.7 cc/g, or from about 0.9 to about 1.4 cc/g.

[0032] The support material may have an average particle size in the range of from about

5 to about 500 microns, or from about 10 to about 300 microns, or from about 5 to about 100 microns.

[0033] It is preferred that the support material, most preferably an inorganic oxide, has a surface area in the range of from about 10 to about 700 m^/g, pore volume in the range of from about 0.1 to about 4.0 cc/g and average particle size in the range of from about 5 to about 500 μηι. More preferably, the surface area of the support material is in the range of from about 50 to about 500 m^/g, pore volume of from about 0.5 to about 3.5 cc/g and average particle size of from about 10 to about 200 μιη. Most preferably the surface area of the support material is in the range is from about 100 to about 400 m^/g, pore volume from about 0.8 to about 3.0 cc/g and average particle size is from about 5 to about 100 μιη. The average pore size of the carrier of the present disclosure typically has pore size in the range of from 10 to lOOOA, preferably 50 to about 500A, and most preferably 75 to about 350A.

[0034] The support materials may be treated chemically, for example with a fluoride compound as described in WO 00/12565. Other supported activators are described in for example WO 00/13792 that refers to supported boron containing solid acid complex.

[0035] In some embodiments, the support material may include a fumed silica available under the trade name CABOSIL™ TS-610, available from Cabot Corporation. Fumed silica is typically a silica with particles 7 to 30 nanometers in size that has been treated with dimethylsilyldichloride such that a majority of the surface hydroxyl groups are capped. In another embodiment the fumed silica utilized has a particle size of less than 40 microns, preferably less than 20 microns or preferably less than 10 microns.

[0036] In some embodiments, the support material may be a partially or totally dehydrated support material. For example, silica dehydrated at temperatures in the range from about 200°C to 900°C, may be contacted with an alumoxane.

Catalyst Compounds

[0037] Any type of polymerization catalyst compounds may be used in the present processes, including liquid-form catalysts, solid catalysts, and heterogeneous or supported catalysts, among others, and may be fed to the reactor as a liquid, slurry (liquid/solid mixture), or as a solid (typically gas transported). Such catalyst compounds may be used to form catalyst compositions disclosed herein, and/or may be used in addition to catalyst compositions disclosed herein for use in producing polymers.

[0038] Liquid-form catalysts should be stable and sprayable or atomizable. These catalysts may be used alone or in various combinations or mixtures. For example, one or more liquid catalysts, one or more solid catalysts, one or more supported catalysts, or a mixture of a liquid catalyst and/or a solid or supported catalyst, or a mixture of solid and supported catalysts may be used. These catalysts may be used with co-catalysts, activators, and/or promoters well known in the art.

[0039] Catalyst compounds useful in embodiments disclosed herein may include, broadly, transition metal catalysts and metallocene catalysts. More specifically, useful catalyst compounds include:

A. Chromium based catalysts, such as those described in U.S. Patent Nos. 3,709,853;

3,709,954; and 4,077,904. B. Vanadium based catalysts, such as vanadium oxychloride and vanadium acetylacetonate, such as described in U.S. Patent No. 5,317,036.

C. Metallocene catalysts, such as those described in U.S. Patent Nos. 6,933,258 and 6,894, 131.

D. Cationic forms of metal halides, such as aluminum trihalides.

E. Cobalt catalysts and mixtures thereof, such as those described in U.S. Patent Nos.

4,472,559 and 4, 182,814.

F. Nickel, iron, and other late-transition metal catalysts and mixtures thereof, such as those described in U.S. Patent Nos. 4, 155,880 and 4, 102,817.

G. Rare earth metal catalysts, i.e., those containing a metal having an atomic number in the Periodic Table of 57 to 103, such as compounds of cerium, lanthanum, praseodymium, gadolinium and neodymium. Especially useful are carboxylates, alcoholates, acetylacetonates, halides (including ether and alcohol complexes of neodymium trichloride), and alkyl derivatives of such metals. In various embodiments, neodymium compounds, particularly neodymium neodecanoate, octanoate, and versatate, are particularly useful rare earth metal catalysts. Rare earth catalysts may be used, for example, to polymerize butadiene or isoprene.

H. Group 15 atom and metal containing catalysts described in, for example, EP 0 893 454 Al, U.S. Patent No. 5,889, 128 and the references cited in U.S. Patent No. 5,889, 128.

I. Any combination of the above to form a mixed catalyst system.

Catalyst Preparation

[0040] One or more alumoxanes may be supported using one or more support materials according to embodiments disclosed herein. For example, one or more alumoxanes may be contacted with a support material. In other embodiments, one or more support materials may be contacted with an alumoxane. In other embodiments, two or more alumoxanes may be contacted with two or more support materials. As used herein, "different support materials" refers to support materials differing in one or more of composition, average particle size, pore diameter, and pore volume, as well as other parameters commonly used to differentiate between support materials.

[0041] In some embodiments, a supported alumoxane is formed by preparing in an agitated, and temperature and pressure controlled vessel a solution of the alumoxane and a suitable solvent, then adding the support material at temperatures from 0°C to 100°C, contacting the support with the alumoxane solution for up to 24 hours, then using a combination of heat and pressure to remove the solvent to produce a free flowing powder. Temperatures during solvent removal can range from 30 to 80°C and pressures from 5 psia to 20 psia (34.5 to 138 kPa). An inert gas sweep can also be used in assist in removing solvent. Alternate orders of addition, such as slurrying the support material in an appropriate solvent then adding the alumoxane, can be used. The dried supported alumoxane may then be heat treated as described above.

[0042] In other embodiments, a supported alumoxane is formed by preparing in an agitated, and temperature and pressure controlled vessel a solution of the alumoxane and a suitable solvent, then adding the support material at temperatures from 0°C to 100°C, and contacting the support with the alumoxane solution for up to 24 hours. The supported alumoxane is then heat treated at elevated temperatures, in the presence of the solvent, as described above. Following heat treatment, a combination of heat and pressure is used to remove the solvent to produce a free flowing powder. Temperatures during solvent removal can range from 30 to 80°C and pressures from 5 psia to 20 psia (34.5 to 138 kPa). An inert gas sweep can also be used in assist in removing solvent. Alternate orders of addition, such as slurrying the support material in an appropriate solvent then adding the alumoxane, can be used.

[0043] Drying of solvent during catalyst preparation is typically conducted commercially at temperatures of less than 80°C and under at least a partial vacuum. It is noted that various references may disclose that solvent removal may be conducted at temperatures of up to 120°C. However, this temperature range corresponds to a broad range of solvents, or where greater than atmospheric pressures may be used, and thus should not be confused with the heat treatment disclosed herein.

[0044] In a preferred method of forming a supported alumoxane, the amount of liquid in which the alumoxane is present is an amount that is less than four times the pore volume of the support material, more preferably less than three times, more preferably less than two times; preferred ranges being from 1.1 times to 3.5 times the pore volume of the support material, and most preferably 1.2 to 3 times the pore volume of the support material. In another embodiment, the amount of liquid in which the alumoxane is present is from one to less than one times the pore volume of the support material utilized in forming the supported alumoxane.

[0045] Procedures for measuring the total pore volume of a porous support are well known in the art. Details of one of these procedures are discussed in Volume 1, Experimental Methods in Catalytic Research (Academic Press, 1968) (specifically see pages 67-96). This preferred procedure involves the use of a classical BET apparatus for nitrogen absorption. Another method well known in the art is described in Innes, Total Porosity and Particle Density of Fluid Catalysts By Liquid Titration, Vol. 28, No. 3, Analytical Chemistry 332-334 (March, 1956).

[0046] The support material may be combined with one or more alumoxanes and then spray dried to form a supported activator. For example, fumed silica is combined with methyl alumoxane and then spray dried to form supported methyl alumoxane. Preferably a support is combined with alumoxane, spray dried and then placed in mineral oil to form a slurry useful in the instant disclosure. The heat treatment of the supported alumoxane may be conducted following combination of the support and alumoxane, following the spray drying, or following slurrying of the supported alumoxane.

[0047] The catalyst compounds (or precursors) may be combined with the supported alumoxane and then spray dried, preferably to form a free flowing powder. Spray drying may be by any means known in the art. See EP A 0 668 295 Bl, U.S. Patent No. 5,674,795 and U.S. Patent No. 5,672,669 and U.S. Patent Application Serial No. 09/464,1 14 filed December 16, 1999, which particularly describe spray drying of supported catalysts. In general one may spray dry the catalysts by placing the catalyst compound and supported alumoxane in solution (allowing the catalyst compound and supported alumoxane to react, if desired), then forcing the solution at high pressures through a nozzle. The solution may be sprayed onto a surface or sprayed such that the droplets dry in midair. One method that may be employed is to disperse the supported alumoxane in toluene, stir in the catalyst compound solution, such as to a slurry concentrations of about 5 to 8 wt%, and allow this mixture to sit as a slurry for as long as 30 minutes with mild stirring or manual shaking to keep it as a suspension before spray-drying. In one preferred embodiment, the makeup of the dried material is about 35-50 wt% alumoxane, 50- 65 wt% support material, and about 2 wt% catalyst compound. Such a spray dried supported alumoxane may then be heat treated as described above.

[0048] When two or more catalyst compounds are used to form a catalyst composition according to embodiments disclosed herein, the two or more catalyst compounds can be added together in the desired ratio when contacted with the supported alumoxane. In other embodiments, more complex procedures are possible, such as addition of a first catalyst compound to the supported alumoxane mixture for a specified reaction time t, followed by the addition of the second catalyst compound solution, mixed for another specified time x, after which the mixture is co-sprayed. Lastly, another additive, such as 1-hexene in about 10 vol% can be present in the supported alumoxane mixture prior to the addition of the first metal catalyst compound. [0049] The heat treated supported alumoxanes disclosed herein may be utilized in a catalyst slurry, which, for the purposes of the present disclosure, is defined to be a suspension of a solid, where the solid may or may not be porous, in a liquid. The catalyst slurry is then introduced into a polymerization reactor. In some embodiments, the catalyst composition may be combined with additional activators, catalyst slurries, or catalyst solutions to form a composition which is then introduced into a polymerization reactor. Solids concentrations in mineral oil may range from about 10 to 30 weight %, preferably 15 to 25 weight %, in some embodiments. In some embodiments, the catalyst composition may be present in a catalyst slurry at concentrations of up to about 90 wt %, preferably at up to about 50 wt %, preferably at up to about 20 wt %, preferably at up to about 10 wt%, more preferably at up to about 5 wt%, more preferably at less than 1 wt%, more preferably between 100 ppm and 1 wt % based upon the weight of the solvent, heat treated supported alumoxane, and the catalyst compound.

[0050] In some embodiments, a catalyst slurry may include one or more activator(s) and support(s) and/or supported activator(s) and/or one more catalyst compound(s). For example, the slurry may include two or more activators (such as a heat treated supported alumoxane according to embodiments disclosed herein and a modified alumoxane) and a catalyst compound, or the slurry may include an activator or a supported activator and more than one catalyst composition according to embodiments disclosed herein. The catalyst slurry may comprise a heat treated supported alumoxane according to embodiments disclosed herein and two catalyst compounds, wherein the two catalyst compounds may be the same or different and wherein they may be added to the slurry separately or in combination.

[0051] In one embodiment, a slurry containing a heat treated supported alumoxane is contacted with a catalyst compound, allowed to react, and thereafter the slurry is contacted with another catalyst compound. In another embodiment the slurry containing a heat treated supported alumoxane is contacted with two catalyst compounds at the same time, and allowed to react.

[0052] The catalyst slurry used in processes disclosed herein is typically prepared by suspending the heat treated supported alumoxane and the catalyst compounds in a liquid diluent. The liquid diluent is typically an alkane having from 3 to 60 carbon atoms, preferably having from 5 to 20 carbon atoms, preferably a branched alkane, or an organic composition such as mineral oil or silicone oil. The diluent employed is preferably liquid under the conditions of polymerization and relatively inert. The concentration of the components in the slurry is controlled such that a desired ratio of catalyst compound(s) to alumoxane (and any additional activators), and/or catalyst compound to catalyst compound is fed into the reactor. [0053] Typically, the catalyst compound and the heat treated supported alumoxane are allowed to contact each other for a time sufficient for at least 50% of the catalyst compounds to be deposited into or on the support, preferably at least 70%, preferably at least 75%, preferably at least 80%, more preferably at least 90%, preferably at least 95%, preferably at least 99%. Times allowed for mixing are up to 10 hours, typically up to 6 hours, more typically 4 to 6 hours. In one embodiment of the present disclosure a catalyst compound will be considered to be in or on the support if the concentration of the catalyst compound in the liquid portion of the slurry is reduced over time after adding the catalyst compound to the slurry. Concentration of the catalyst compound in the liquid diluent may be measured for example, by inductively coupled plasma spectroscopy (ICPS), or by ultraviolet (UV) spectroscopy, after standardization with a calibration curve prepared at the appropriate concentration range, as is known in the art. Thus for example, 70% of a catalyst compound will be considered to have deposited in or on a support if the concentration of the catalyst compound in the liquid (not including the support) is reduced by 70% from its initial concentration.

[0054] In some embodiment, a heat treated supported alumoxane, preferably methyl alumoxane or modified methyl alumoxane, is dispersed in a liquid, such as degassed mineral oil, and then one or more catalyst compounds are added to the dispersion and mixed to form the catalyst slurry. The catalyst compounds are preferably added to the dispersion as a solid, powder, solution or a slurry, preferably a slurry of mineral oil. If more than one catalyst compound is added to the dispersion, the catalyst compounds can be added sequentially, or at the same time. The catalyst compound may be added to the slurry in solid or powder form.

[0055] The catalyst slurry may comprise mineral oil and have a viscosity of about 130 to about 2000 cP at 20°C, more preferably about 180 to about 1500 cP at 20°C and even more preferably about 200 to about 800 cP at 20°C as measured with a Brookfield model LVDV-III Rheometer housed in a nitrogen purged drybox (in such a manner that the atmosphere is substantially free of moisture and oxygen, i.e. less than several ppmv of each). The catalyst slurries may be made in a nitrogen purged drybox, and rolled in their closed glass containers until immediately before the viscosity measurements are made, in order to ensure that they are fully suspended at the start of the measurement. Temperature of the viscometer is controlled via an external temperature bath circulating heat transfer fluid into the viscometer. The rheometer was fitted with the appropriate spindle for the test material as specified in the unit's application guide. Typically, a SC4-34 or SC4-25 spindle was used. Data analysis was performed using Rheocalc VI.1 software, copyright 1995, Brookfield Engineering Laboratories, preferably purchased and used with the unit. [0056] In some embodiments, an aluminum alkyl, an ethoxylated aluminum alkyl, additional alumoxane, an anti-static agent or a borate activator, such as a Ci to C ₁₅ alkyl aluminum (for example tri-isobutyl aluminum, trimethyl aluminum or the like), a Ci to C ₁₅ ethoxylated alkyl aluminum or methyl alumoxane, ethyl alumoxane, isobutylalumoxane, modified alumoxane or the like are added to the polymerization reactor, either individually or in combination with catalyst compositions according to embodiments disclosed herein. The alkyls, antistatic agents, borate activators and/or alumoxanes may be added directly to the combination of the solution and the slurry, or may be added via an additional alkane (such as isopentane, hexane, heptane, and or octane) carrier stream. Preferably, the additional alkyls, antistatic agents, borate activators and/or alumoxanes are present in the polymerization reactor at up to about 500 ppm, more preferably at about 1 to about 300 ppm, more preferably at 10 to about 300 ppm, more preferably at about 10 to about 100 ppm. Preferred carrier streams include isopentane and or hexane. The alkane may be added to the mixture of the slurry and the solution, typically at a rate of about 0.5 to about 60 lbs/hr (27 kg/hr). Likewise carrier gas, such as nitrogen, argon, ethane, propane and the like may be added in-line to the mixture of the catalyst composition and/or additional component feeds. Typically the carrier gas may be added at the rate of about 1 to about 100 lb/hr (0.4 to 45 kg/hr), preferably about 1 to about 50 lb/hr (5 to 23 kg/hr), more preferably about 1 to about 25 lb/hr (0.4 tol 1 kg/hr).

Polymerization Processes

[0057] The catalyst compositions prepared according to embodiments disclosed herein are suitable for use in any prepolymerization and/or polymerization process over a wide range of temperatures and pressures. Polymerization temperatures may be in the range of from -60°C to about 280°C, preferably from 50°C to about 200°C, and the pressures employed may be in the range from about 1 atmosphere to about 500 atmospheres or higher.

[0058] The catalyst compositions disclosed herein may be fed to the polymerization reactor utilizing a slurry feeder. A slurry feeder, for example, is described U.S. Patent 5,674,795.

[0059] In various embodiments, a solution of a metallocene compound and optional activator can be combined with a catalyst composition as disclosed herein and then introduced into a polymerization reactor.

[0060] Polymerization processes useful in embodiments disclosed herein include solution, gas phase, slurry phase and a high pressure process or a combination thereof. Particularly preferred is a gas phase or slurry phase polymerization of one or more olefins at least one of which is ethylene or propylene and more preferably ethylene.

[0061] The catalyst composition disclosed herein may be used in a polymerization process of one or more olefin monomers having from 2 to 30 carbon atoms, preferably 2 to 12 carbon atoms, and more preferably 2 to 8 carbon atoms. The present disclosure is particularly well suited to the polymerization of two or more olefin monomers of ethylene, propylene, butene-1, pentene-1, 4-methyl-pentene-l, hexene-1, octene-1 and decene-1.

[0062] Other monomers useful in the process of the present disclosure include ethylenically unsaturated monomers, diolefins having 4 to 18 carbon atoms, conjugated or nonconjugated dienes, polyenes, vinyl monomers and cyclic olefins. Non-limiting monomers useful in the present disclosure may include norbornene, norbornadiene, isobutylene, isoprene, vinylbenzocyclobutane, styrenes, alkyl substituted styrene, ethylidene norbornene, dicyclopentadiene and cyclopentene.

[0063] Preferably, a copolymer of ethylene is produced, where with ethylene, a comonomer having at least one alpha-olefin having from 3 to 15 carbon atoms, preferably from 4 to 12 carbon atoms, and most preferably from 4 to 8 carbon atoms, is polymerized in a gas phase process.

[0064] In some embodiments, ethylene or propylene are polymerized with at least two different comonomers, optionally one of which may be a diene, to form a terpolymer.

[0065] The mole ratio of comonomer to ethylene, JC2, where C _x is the amount of comonomer and C2 is the amount of ethylene, may be between about 0.001 to 0.200 and more preferably between about 0.002 to 0.008.

[0066] Typically in a gas phase polymerization process a continuous cycle is employed where in one part of the cycle of a reactor system, a cycling gas stream, otherwise known as a recycle stream or fluidizing medium, is heated in the reactor by the heat of polymerization. This heat is removed from the recycle composition in another part of the cycle by a cooling system external to the reactor. Generally, in a gas fluidized bed process for producing polymers, a gaseous stream containing one or more monomers is continuously cycled through a fluidized bed in the presence of a catalyst under reactive conditions. The gaseous stream is withdrawn from the fluidized bed and recycled back into the reactor. Simultaneously, polymer product is withdrawn from the reactor and fresh monomer is added to replace the polymerized monomer. See U.S. Patent Nos. 4,543,399, 4,588,790, 5,028,670, 5,317,036, 5,352,749, 5,405,922, 5,436,304, 5,453,471, 5,462,999, 5,616,661 and 5,668,228. [0067] The reactor pressure in a gas phase process may vary from about 100 psig (690 kPa) to about 600 psig (4138 kPa), preferably in the range of from about 200 psig (1379 kPa) to about 400 psig (2759 kPa), more preferably in the range of from about 250 psig (1724 kPa) to about 350 psig (2414 kPa).

[0068] The reactor temperature in a gas phase process may vary from about 30°C to about 120°C, preferably from about 60°C to about 1 15°C, more preferably in the range of from about 70°C to 110°C, and most preferably in the range of from about 70°C to about 95°C.

[0069] Other gas phase processes contemplated include series or multistage polymerization processes. Also gas phase processes contemplated include those described in U.S. Patent Nos. 5,627,242, 5,665,818 and 5,677,375, and European publications EP-A- 0 794 200 EP-Bl-0 649 992, EP-A- 0 802 202 and EP-B- 634 421.

[0070] In a preferred embodiment, polymerization processes useful in the present disclosure are capable of producing greater than 500 lbs of polymer per hour (227 Kg/hr) to about 200,000 lbs/hr (90,900 Kg/hr) or higher of polymer, or greater than 1000 lbs/hr (455 Kg/hr), or greater than 10,000 lbs/hr (4540 Kg/hr), or greater than 25,000 lbs/hr (1 1,300 Kg/hr), or greater than 35,000 lbs/hr (15,900 Kg/hr), or greater than 50,000 lbs/hr (22,700 Kg/hr), or greater than 65,000 lbs/hr (29,000 Kg/hr) to greater than 100,000 lbs/hr (45,500 Kg/hr).

[0071] Particle form polymerization processes, or a slurry process where the temperature is kept below the temperature at which the polymer goes into solution, are described in for instance U.S. Patent No. 3,248, 179. Other examples of slurry processes are described in U.S. Patent No. 4,613,484 and 5,986,021.

[0072] Examples of solution processes are described in U.S. Patent Nos. 4,271,060,

5,001,205, 5,236,998, 5,589,555 and 5,977,251 and PCT WO 99/32525 and PCT WO 99/40130.

[0073] A preferred process of the present disclosure is where the process, preferably a slurry or gas phase process is operated in the presence of a metallocene catalyst system according to embodiments disclosed herein and in the absence of or essentially free of any scavengers, such as triethylaluminum, trimethylaluminum, tri-isobutylaluminum and tri-n- hexylaluminum and diethyl aluminum chloride, dibutyl zinc and the like. This preferred process is described in PCT publication WO 96/08520 and U.S. Patent Nos. 5,712,352 and 5,763,543.

[0074] In one embodiment of the present disclosure, olefin(s), preferably C2 to C30 olefin(s) or alpha-olefin(s), preferably ethylene or propylene or combinations thereof are prepolymerized in the presence of a metallocene catalyst systems according to embodiments disclosed herein prior to the main polymerization. The prepolymerization can be carried out batchwise or continuously in gas, solution or slurry phase including at elevated pressures. The prepolymerization can take place with any olefin monomer or combination and/or in the presence of any molecular weight controlling agent such as hydrogen. For examples of prepolymerization procedures, see U.S. Patent Nos. 4,748,221, 4,789,359, 4,923,833, 4,921,825, 5,283,278 and 5,705,578 and European publication EP-B-0279 863 and PCT Publication WO 97/44371.

[0075] In one embodiment, toluene is not used in the catalyst preparation or polymerization processes of the present disclosure.

Polymer Products

[0076] Polymers produced by the process of the present disclosure can be used in a wide variety of products and end-use applications. The polymers produced include linear low density polyethylene, elastomers, plastomers, high density polyethylenes, medium density polyethylenes, low density polyethylenes, multimodal or bimodal high molecular weight polyethylenes, polypropylene and polypropylene copolymers.

[0077] The polymers, typically ethylene based polymers, have a density in the range of from 0.86g/cc to 0.97 g/cc, depending on the desired use. For some applications a density in the range of from 0.88 g/cc to 0.920 g/cc is preferred while in other applications, such as pipe, film and blow molding, a density in the range of from 0.930 g/cc to 0.965 g/cc is preferred. For low density polymers, such as for film applications, a density of 0.910 g/cc to 0.940 g/cc is preferred. Density is measured in accordance with standard ASTM methods.

[0078] The polymers produced by the process of the present disclosure may have a molecular weight distribution, a ratio of weight average molecular weight to number average molecular weight (M _w /M _n ), of greater than 1.5 to about 70. In some embodiments the polymer produced has a narrow M _w /M _n of about 1.5 to 15, while in other embodiments the polymer produced has an M _w /M _n of about 30 to 50. Also, the polymers of the present disclosure may have a narrow or broad composition distribution as measured by Composition Distribution Breadth Index (CDBI). Further details of determining the CDBI of a copolymer are known to those skilled in the art. See, for example, PCT Patent Application WO 93/03093.

[0079] The polymers produced may have CDBI's generally in the range of greater than

50% to 100%, preferably 99%, preferably in the range of 55% to 85%, and more preferably 60% to 80%, even more preferably greater than 60%, still even more preferably greater than 65%.

[0080] In another embodiment, polymers produced may have a CDBI less than 50%, more preferably less than 40%, and most preferably less than 30%. [0081] The polymers produced may have a melt index (MI) or (I ₂ ) as measured by

ASTM-D-1238-E in the range from 0.01 dg/min to 1000 dg/min, more preferably from about 0.01 dg/min to about 100 dg/min, even more preferably from about 0.01 dg/min to about 50 dg/min, and most preferably from about 0.1 dg/min to about 10 dg/min.

[0082] The polymers produced may have a melt index ratio (I ₂ i/I ₂ ) (hi is measured by

ASTM-D-1238-F) of from 10 to less than 25, more preferably from about 15 to less than 25.

[0083] The polymers produced may have a melt index ratio (I ₂ i/I ₂ ) (hi is measured by

ASTM-D-1238-F) of from preferably greater than 25, more preferably greater than 30, even more preferably greater that 40, still even more preferably greater than 50 and most preferably greater than 65. In an embodiment, the polymer of the present disclosure may have a narrow molecular weight distribution and a broad composition distribution or vice-versa, and may be those polymers described in U.S. Patent No. 5,798,427.

[0084] In one embodiment the polymers produced by the present disclosure have a multimodal molecular weight distribution (Mw/Mn) or, typically, bimodal molecular weight distribution. In a preferred embodiment, the polymer produced has a density of 0.93 to 0.96 g/cc, an MI (I ₂ ) of 0.03 - O. lOg/lOmin, an FI (I ₂₁ ) of 4-12 g/ lOmin, an MFR (I ₂₁ /I ₂ ) of 80-180, an overall Mw of 200,000 to 400,000, an overall Mn of 5,000-10,000 and an Mw/Mn of 20-50. Preferably the low molecular weight fraction (-500— 50,000) has a density of 0.935-0.975 g/cc and the high molecular weight fraction (-50,000 - - 8,000,000) has a density of 0.910 - 0.950 g/cc. These polymers are particularly useful for film and pipe, especially PE-100 pipe applications.

[0085] In another embodiment the polymer produced by the present disclosure has a bimodal molecular weight distribution (Mw/Mn). In a preferred embodiment, the polymer produced has a density of 0.93 to 0.97 g/cc, an MI (I ₂ ) of 0.02 - 0.5 g/lOmin, an FI (I ₂₁ ) of 10-40 g/ lOmin, an MFR (I ₂₁ /I ₂ ) of 50-300, an Mw of 100,000 to 500,000, an Mn of 8,000-20,000 and an Mw/Mn of 10-40. These polymers are particularly useful for blow molding applications. These bimodal polymers exhibited extraordinary Bent Strip ESCR (environmental stress crack resistance) performance, which far exceeds the performance of unimodal HDPE. Also, the blow molded bottles trimmed easier and had opaque finish, which is preferred over translucent finish of unimodal HDPE.

[0086] In yet another embodiment, propylene based polymers are produced in the process of the present disclosure. Propylene polymers are described in U.S. Patent Nos. 4,794,096, 3,248,455, 4,376,851, 5,036,034 and 5,459,1 17. [0087] The polymers of the present disclosure may be blended and/or coextruded with any other polymer. Non-limiting examples of other polymers include linear low density poly ethylenes produced via conventional Ziegler-Natta and/or metallocene catalysis, elastomers, plastomers, high pressure low density polyethylene, high density polyethylenes, polypropylenes and the like.

[0088] Polymers produced by the process of the present disclosure and blends thereof are useful in such forming operations as film, sheet, and fiber extrusion and co-extrusion as well as blow molding, injection molding and rotary molding.

[0089] In order to provide a better understanding of the present disclosure including representative advantages thereof, the following examples are offered.

EXAMPLES

Example 1 - Preparation of MAO Treated Davison 948 Silica - SMAO with 17.5 wt % aluminum loading.

[0090] Example 1A: Inside a N2 glove box, 45.06 g of 30 wt % MAO solution in toluene (supplied from Albemarle) is added to a 250 ml round bottom flask with magnetic stir bar. 25.0 g of 200°C nitrogen dehydrated Davison 948 silica is then added slowly to the flask. The slurry is then stirred for 2 hours at ambient temperature and then vacuum dried at 40°C on a rotavap.

[0091] Example IB: procedure used was the same as for Example 1A, except that the

MAO/silica reaction temperature is at 100°C.

[0092] Example 1C: procedure used was the same as for Example 1A, except that the

MAO/silica reaction temperature is at 100°C and the product is heat treated at a temperature of 1 10°C.

Example 2 - Preparation of Solvent Washed SMAO

[0093] Example 2A: Twenty grams of SMAO collected from example 1A is washed with 50 ml of anhydrous cyclohexane twice, the product is then filtered and dried on rotavap at 70°C.

[0094] Example 2B: Twenty grams of SMAO collected from example IB is washed with

50 ml of anhydrous cyclohexane twice, the product is then filtered and dried on a rotavap at 70°C. [0095] Example 2C: Twenty grams of SMAO collected from example 1C is washed with

50 ml of anhydrous cyclohexane twice, the product is then filtered and dried on rotavap at 70°C. Example 3 - Preparation of Supported Metallocene Catalyst

[0096] 7.7 grams of each SMAO products collected from example 1A, IB, 1C and 2A,

2B, 2C are placed into separate 125 ml serum bottles with stir bar. Anhydrous toluene (30 ml) is then added into each bottle. 0.136 g of metallocene compound bis(l -methyl, 3- n-butyl Cp) ₂ ZrCl ₂ (available from Albemarle; pre-dissolved in toluene) is added into the SMAO slurry. The mixture is stirred at ambient temperature for 30 minutes. The slurry is dried with a N2 purge at 60°C. The final yellow, free-flowing catalysts are labeled as 3A, 3B, 3C and 3AW, 3BW, 3CW, where "W" is denoted as a washed catalyst.

Polymerization Tests

[0097] Ethylene-hexene copolymerization tests with each catalyst sample are conducted in a 2.2 liter autoclave reactor. After the pre-baked reactor is cooled to ambient temperature under a nitrogen blanket, 0.2 mmol of triethyl aluminum and 60 ml of anhydrous hexene-1 are added to the reactor. The reactor is then filled with 80 ml isobutane. After raising the reactor temperature to 85°C, 100 mg of supported catalyst is pushed into the reactor by ethylene. The polymerization temperature is maintained at 85°C, total reactor pressure is kept at 325 psig. After 40 minutes of polymerization time, the reaction is terminated by turning off the heat supply and venting off the ethylene and isobutane. The resulting polymer is collected, dried and weighed. The results are listed in Table 1.

Table- 1

Comparative Example 4 - Preparation of Supported Metallocene Catalyst Through non-SMAO Method

[0098] Inside a N2 filled glove box, 8.24 g of 30 wt % MAO in toluene, 20 ml anhydrous toluene are added to a 125 ml serum bottle with stir bar. Metallocene bis (1 -methyl, 3- n-butyl Cp) ₂ ZrCl ₂ , 0.136 g pre-dissolved in toluene, is then added to the bottle. The mixture is stirred at ambient temperature for 15 minutes. ES757 silica (available from PQ Corp.) pre- dehydrated at 200°C under 2 is added, and the slurry is stirred at ambient for 15 minutes. 0.036 g AS-990 (an antistatic agent available from Ciba) is added while stirring the mixture. After 15 minutes, the slurry is filtered on a fritted funnel. The solid is washed with 30 ml toluene and then 30 ml n-hexane. The solid is then dried under N2 purge at 75 °C. The estimated Al loading is 16 wt %.

Example 5 - Preparation of MAO Treated ES757 silica - SMAO with 16.0 wt % aluminum loading

[0099] In a 125 ml serum bottle with stir bar, 7.7 g of ES757 (200°C dehydrated under

N ₂ ) and 30 ml toluene is added. 12.7 g of 30 wt % of MAO in toluene is then added slowly while stirring. The mixture is reacted for 1 hour at ambient temperature. The slurry is filtered using a fritted funnel. The solid is washed with 30 ml toluene twice and once with 30 ml n- hexane. SMAO product is vacuum dried at ambient temperature overnight. The aluminum loading is estimated to be 16 wt %.

[00100] The dry SMAO is then divided to 3 parts:

i) Example 5A: 3.79 g with no treatment.

ii) Example 5B: 3.73 g is heat treated on rotovap at 80°C for 2 hours.

iii) Example 5C 3.67 g is heat treated on rotovap at 100°C for 2 hours.

Example 6 - Preparation of Metallocene Catalyst on SMAO (ES757 silica)

[00101] Example 6A: SMAO from Example 5A is added into a 125 ml bottle, and 30 ml toluene is also added. While stirring, 0.069 g bis (1 -methyl, 3 -n-butyl Cp)2ZrCl2 in toluene is added. The mixture is stirred at ambient temperature for 30 minutes. 0.018 g AS-990 is added and the slurry is stirred for another 15 minutes. The solid is dried under 2 purge at 75°C.

[00102] Example 6B: SMAO from Example 5B is added into a 125 ml bottle, and 30 ml toluene is also added. While stirring, 0.068 g bis (1 -methyl, 3 -n-butyl Cp)2ZrCl2 in toluene is added. The mixture is stirred at ambient temperature for 30 minutes. 0.018 g AS-990 is added and the slurry is stirred for another 15 minutes. The solid is dried under 2 purge at 75°C. [00103] Example 6C: SMAO from Example 5C is added into a 125 ml bottle, and 30 ml toluene is also added. While stirring, 0.067 g bis (1 -methyl, 3 -n-butyl Cp) ₂ ZrCl ₂ in toluene is added. The mixture is stirred at ambient temperature for 30 minutes. 0.017 g AS-990 is added and the slurry is stirred for another 15 minutes. The solid is dried under ₂ purge at 75°C.

[00104] Polymerization tests of the catalysts from Comparative example 4 and examples

6A, 6B and 6C are conducted in the manner as described above. The test results are listed in Table 2.

Table 2

[00105] As shown by the results in Table 1 and Table 2 above, heat treatment of the catalyst at a temperature of at least 80°C results in a marked improvement in catalyst activity.

[00106] As described above catalyst compositions according to embodiments disclosed herein include a heat treated supported alumoxane subsequently contacted with a polymerization catalyst compound. It has surprisingly been found that the activity (productivity) of the resulting catalyst may be substantially increased due to heat treatment prior to contact with the catalyst compound.

[00107] Catalyst compositions according to embodiments disclosed herein, having improved activity (productivity) may provide for a reduced catalyst cost, per pound of polymer produced, as compared to conventionally prepared supported alumoxane catalyst compositions. The reduced costs may result as productivity of the catalyst is improved while maintaining a similar raw material cost.

[00108] The phrases, unless otherwise specified, "consists essentially of and "consisting essentially of do not exclude the presence of other steps, elements, or materials, whether or not, specifically mentioned in this specification, so long as such steps, elements, or materials, do not affect the basic and novel characteristics of the invention, additionally, they do not exclude impurities and variances normally associated with the elements and materials used. [00109] Only certain ranges are explicitly disclosed herein. However, ranges from any lower limit may be combined with any upper limit to recite a range not explicitly recited, as well as, ranges from any lower limit may be combined with any other lower limit to recite a range not explicitly recited, in the same way, ranges from any upper limit may be combined with any other upper limit to recite a range not explicitly recited.

[00110] All documents cited herein are fully incorporated by reference for all jurisdictions in which such incorporation is permitted and to the extent such disclosure is consistent with the description of the present invention.