IMPROVED METHOD FOR PREPARING SUPPORTED METALLOCENE CATALYST SYSTEMS

Abstract: This invention relates generally to supported metallocene catalyst systems and to methods for their production and use. Specifically, this invention relates to a method for preparing supported metallocene catalyst systems using an aliphatic solvent. The catalyst systems prepared by these methods exhibit increased activity.

Description: IMPROVED METHOD FOR PREPARING SUPPORTED METALLOCENE CATALYST SYSTEMS FIELD OF THE INVENTION This invention relates generally to supported metallocene catalyst systems and to methods for their production and use. Specifically, this invention relates to methods for preparing supported metallocene catalyst systems using an aliphatic solvent. BACKGROUND A number of methods for preparing supported metallocene catalyst systems have been reported. For example, U. S. Patent No. 5,240,894 describes a method wherein the metallocene and activator are precontacted and then deposited on the support material. The catalyst system is then dried to remove residual solvent and optionally prepolymerized. WO 94/28034 describes a similar method wherein the metallocene is specifically a bridged bis indenyl compound. U. S. Patent No. 5,373,072 describes a method involving the use of undehydrated silica gel. U. S. Patent No. 5,468,702 describes the use of an aged activator to prepare the supported metallocene catalyst system. And, U. S. Patent No. 5,516,737 describes separately supporting the activator and metallocene. In all of these patents, an aromatic hydrocarbon, typically toluene, serves as the solvent not only for the alumoxane activator but also for the metallocene and alumoxane reaction. Typically, the metallocene and alumoxane are deposited on the support material in a toluene solution. Toluene is the solvent of choice because it easily dissolves alumoxanes and/or activated metallocenes. Once the catalyst components are deposited on the support, the catalyst system is usually dried prior to use even though it is known that drying conditions often substantially decrease catalyst system activity. The present inventor has discovered that the activity of supported metallocene catalyst systems is substantially increased when an aliphatic solvent is used either in place of or in conjunction with typical solvents such as toluene. SUMMARY This invention relates to a method for forming a supported metallocene catalyst system comprising: (a) reacting metallocene and an alumoxane activator to form a catalyst solution; and (b) mixing the catalyst solution with support material in the presence of aliphatic solvent. In another embodiment this invention relates to a method for forming a supported metallocene catalyst system comprising: (a) reacting metallocene and an alumoxane activator to form a catalyst solution; (b) mixing aliphatic hydrocarbon solvent with support material; and (c) combining the catalyst solution with the mixture. In another embodiment this invention relates to a method for forming a supported metallocene catalyst system comprising: (a) reacting metallocene and a first alumoxane portion to form a first catalyst solution; (b) combining aliphatic solvent and support material to form a mixture; (c) combining the first catalyst solution with the mixture; and then (d) adding a second alumoxane portion. DETAILED DESCRIPTION Catalyst System Components Metallocenes As used herein "metallocene" refers generally to compounds represented by the formula Cp MR n X, wherein Cp is a cyclopentadienyl ring which may be substituted, or derivative thereof which may be substituted, M is a Group 4, 5, or 6 transition metal, for example titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum and tungsten, R is a hydrocarbyl group or hydrocarboxy group having from one to 20 carbon atoms, X is a halogen, and m=l-3, n=0-3, q=0-3, and the sum of m+n+q is equal to the oxidation state of the transition metal. Methods for making and using metallocenes are very well known in the art. For example, metallocenes are detailed in United States Patent Nos. 4,530,914; 4,542,199; 4,769,910; 4,808,561; 4,871,705; 4,933,403; 4,937,299; 5,017,714; 5,026,798; 5,057,475; 5,120,867; 5,278,119; 5,304,614; 5,324,800; 5,350,723; and 5,391,790 each fully incorporated herein by reference. Preferred metallocenes are those represented by the formula: wherein M is a metal of Group 4, 5, or 6 of the Periodic Table preferably, zirconium, hafnium and titanium, most preferably zirconium; R! and R^ are identical or different, preferably identical, and are one of a hydrogen atom, a Cj-Cio alkyl group, preferably a C1-C3 alkyl group, a C\-C\ Q alkoxy group, preferably a C1 -C3 alkoxy group, a ^-C\ Q aryl group, preferably a aryloxy group, preferably a Cg-Cg aryloxy group, a C2-C10 alkenyl group, preferably a C2-C4 alkenyl group, a C7-C40 arylalkyl group, preferably a C7-C10 arylalkyl group, a C7-C40 alkylaryl group, preferably a C7-C12 alkylaryl group, a Cg-C Q arylalkenyl group, preferably a arylalkenyl group, or a halogen atom, preferably chlorine; R and R are hydrogen atoms; R^ and R^ are identical or different, preferably identical, are one of a halogen atom, preferably a fluorine, chlorine or bromine atom, a CI -CJO alkyl group, preferably a C1-C4 alkyl group, which may be halogenated, a ^-C\Q aryl group, which may be halogenated, preferably a Cg-Cg aryl group, a C2-C10 alkenyl group, preferably a C2-C4 alkenyl group, a C7-C40 -arylalkyl group, preferably a C7-C10 arylalkyl group, a C7-C40 alkylaryl group, preferably a C7- Cj2 alkylaryl group, a Cg-C4o arylalkenyl group, preferably a C -C]2 arylalkenyl group, a -NR2 15 , -SR 15 , -OR 15 , -OSiR3 15 or -PR 2 15 radical, wherein R 15 is one of a halogen atom, preferably a chlorine atom, a CJ-CJ Q alkyl group, preferably a C1-C3 alkyl group, or a C^-C\Q aryl group, preferably a Cβ-CQ aryl group; R 7 is R 1 RU RU R11 M2 . M 2 M2 M2 (CR 2 13 )- R 2 R 2 R12 R12 R11 R11 R11 o- M2 0- M2 R 12 R12 R 12 -BCR 1 ϊ)-> -A1 R 1 !)-, -Ge-, -Sn-, -O-, -S-, -SO-, -SO 2 -, -N(R Ϊ l )-, -CO-, - P(R π )-, or -P(O)(R π )-; wherein: R 1 *, R ^ and R 1 ^ are identical or different and are a hydrogen atom, a halogen atom, a C1-C20 al group, preferably a CJ-CJO alkyl group, a C1 -C20 fluoroalkyl group, preferably a CJ-CJO fluoroalkyl group, a C6-C30 aryl group, preferably a C6-C20 ary 1 8 Tau P ^ a 6-C30 fluoroaryl group, preferably a Cg-C20 fluoroaryl group, a C1-C20 alkoxy group, preferably a C\-C\Q alkoxy group, a C2-C20 alkenyl group, preferably a C2-C10 alkenyl group, a C7-C40 arylalkyl group, preferably a C7-C20 arylalkyl group, a C -C4o arylalkenyl group, preferably a Cg-C22 arylalkenyl group, a C7-C40 alkylaryl group, preferably a C7-C20 alkylaryl group or R 1 1 and R 12 , or R 1 1 and R 13 , together with the atoms binding them, can form ring systems; M 2 is silicon, germanium or tin, preferably silicon or germanium, most preferably silicon; R8 and R are identical or different and have the meanings stated for R ' ; m and n are identical or different and are zero, 1 or 2, preferably zero or 1 , m plus n being zero, 1 or 2, preferably zero or 1 ; and the radicals R 1 ^ are identical or different and have the meanings stated for R 1 !, R 12 and R 3 . Two adjacent R 1 ^ radicals can be joined together to form a ring system, preferably a ring system containing from 4-6 carbon atoms. Alkyl refers to straight or branched chain substituents. Halogen (halogenated) refers to fluorine, chlorine, bromine or iodine atoms, preferably fluorine or chlorine. Particularly preferred metallocenes are compounds of the structures (A) and (B): wherein: M 1 is Zr or Hf, R 1 and R 2 are methyl or chlorine, and R 5 , R 6 R 8 , R^R 1 ^, R 1 and R 2 have the above-mentioned meanings. These chiral metallocenes may be used as a racemate for the preparation of highly isotactic polypropylene copolymers. It is also possible to use the pure R or S form. An optically active polymer can be prepared with these pure stereoisomeric forms. Preferably the meso form of the metallocene is removed to ensure the center (i.e., the metal atom) provides stereoregular polymerization. Separation of the stereoisomers can be accomplished by known literature techniques. For special products it is also possible to use rac/meso mixtures. Generally, these metallocenes are prepared by a multi-step process involving repeated deprotonations/metallations of the aromatic ligands and introduction of the bridge and the central atom by their halogen derivatives. The following reaction scheme illustrates this generic approach: H 2 R c + ButylLi > HR°Li X-(CR8R 9 ) m -R 7 -(CR 8 R 9 ) n -X _ H 2 R d + ButylLi ) HR d Li HRC-(CR 8 R 9 ) m -R 7 -(CR 8 R 9 ) n -R d H 2 Butyl Li -> LiR C -(CR 8 R 9 ) m -R 7 -(CR 8 R 9 ) n -R d Li MICI4 > (R β RθCJm - R I C (R 8 R 9 C)m - RC I I Cl R 1 Li R1 R7 ιyι i ; R7 Ml I I Cl Cl (R8R9c) n • Rd (R8R9 C ) n Rd Additional methods for preparing metallocenes are fully described in the Journal of Organometallic Chem., volume 288. (1985), pages 63-67, and in EP-A- 320762, both of which are herein fully incorporated by reference. Illustrative but non-limiting examples of preferred metallocenes include: Dimethylsilandiylbis(2-methyl-4-phenyl- 1 -indenyl)ZrCl2 Dimethylsilandiylbis(2-methyl-4,5-benzoindenyl)ZrCl2; Dimethylsilandiylbis(2-methyl-4,6-diisopropylindenyl)ZrCl2; Dimethylsilandiylbis(2-ethyl-4-phenyl- 1 -indenyl)ZrCl2; Dimethylsilandiylbis (2-ethyl-4-naphthyl- 1 -indenyl)ZrCl2, Phenyl(methyl)silandiylbis(2-methyl-4-phenyl- 1 -indenyl)ZrCl2, Dimethylsilandiylbis(2-methyl-4-( 1 -naphthyl)- 1 -indenyl)ZrCl2, Dimethylsilandiylbis(2-methyl-4-(2-naphthyl)- 1 -indenyl)ZrCl2, Dimethylsilandiylbis(2-methyl-indenyl)ZrCl2, Dimethylsilandiylbis(2-methyl-4, 5-diisopropyl- 1 -indenyl)ZrCl2, Dimethylsilandiylbis(2,4,6-trimethyl- 1 -indenyl)ZrCl2, Phenyl(methyl)silandiylbis(2-methyl-4,6-diisopropyl-l-indenyl)ZrCl2, 1 ,2-Ethandiylbis(2-methyI-4,6-diisopropyl-l -indenyI)ZrCl2, 1 ,2-Butandiylbis(2-methyl-4,6-diisopropyl- 1 -indenyl)ZrCl2, Dimethylsilandiylbis(2-methyl-4-ethyI- 1 -indenyl)ZrCl2, Dimethylsilandiylbis(2-methyl-4-isopropyl- 1 -indenyl)ZrCl2, Dimethylsilandiylbis(2-methyl-4-t-butyl- 1 -indenyl)ZrCl2, Phenyl(methyl)silandiylbis(2-methyl-4-isopropyl- 1 -indenyl)ZrCl2, Dimethylsilandiylbis(2-ethyl-4-methyl- 1 -indenyl)ZrCl2, Dimethylsilandiylbis(2,4-dimethyl- 1 -indenyl)ZrCl2, Dimethylsilandiylbis(2-methyl-4-ethyl- 1 -indenyl)ZrCl2, Dimethylsilandiylbis(2-methyl-α-acenaphth- 1 -indenyl)ZrCl2, Phenyl(methyl)silandiylbis(2-methyl-4,5-benzo- 1 -indenyl)ZrCl2, Phenyl(methyI)silandiylbis(2-methyl-4, 5-(methylbenzo)- 1 -indenyl)ZrCl2, Phenyl(methyI)silandiylbis(2-methyl-4, 5-(tetramethylbenzo)- 1 -indenyl)ZrCl2, Phenyl(methyl)silandiylbis(2-methyl-a-acenaphth- 1 -indenyl)ZrCl2, l,2-Ethandiylbis(2-methyl-4,5-benzo-l-indenyl)ZrCl2, 1 ,2-Butandiylbis(2-methyl-4,5-benzo- 1 -indenyl)ZrCl2, DimethylsiIandiylbis(2-methyl-4, 5 -benzo- 1 -indenyl)ZrCl2, 1 ,2-Ethandiylbis(2,4,7-trimethyl- 1 -indenyl)ZrCl2, Dimethylsilandiyibis(2-methyl- 1 -indenyl)ZrCl2, 1 ,2-Ethandiylbis(2-methyl- 1 -indenyl)ZrCl2, Phenyl(methyl)silandiylbis(2-methyl- 1 -indenyl)ZrCl2, Diphenylsilandiylbis(2-methyl- 1 -indenyl)ZrCl2, 1 ,2-Butandiylbis(2-methyl- 1 -indenyl)ZrCl2, Dimethylsilandiylbis(2-ethyl- 1 -indenyl)ZrCl2, Dimethylsilandiylbis(2-methyl-5-isobutyl- 1 -indenyl)ZrCl2, Phenyl(methyI)silandiylbis(2-methyl-5-isobutyl-l-indenyl)ZrCl2, Dimethylsilandiylbis(2-methyl-5-t-butyl- 1 -indenyl)ZrCl2, Dimethylsilandiylbis(2,5,6-trimethyl-l-indenyl)ZrCl2, and the like. These preferred metallocene catalyst components are described in detail in U.S. Patent Nos. 5,145,819; 5,243,001; 5,239,022; 5,329,033; 5,296,434; 5,276,208; and 5,374,752; and EP 549 900 and 576 970 all of which are herein fully incorporated by reference. Activators Metallocenes are generally used in combination with some form of activator in order to create an active catalyst system. The term "activator" is defined herein to be any compound or component, or combination of compounds or components, capable of enhancing the ability of one or more metallocenes to polymerize olefins to polyolefins. For this invention, alklyalumoxanes are preferably used as activators, most preferably methylalumoxane (MAO). Generally, alkylalumoxanes contain 5 to 40 of the repeating units: R — R- -)x*— A1R 2 for linear species and for cyclic species where R is a Cj-Cg alkyl including mixed alkyls Particularly preferred are the compounds in which R is methyl Alumoxane solutions, particularly methylalumoxane solutions, may be obtained from commercial vendors as solutions having various concentrations There are a variety of methods for preparing alumoxane, 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 and EP-A-0 561 476, EP-B1-0 279 586, EP-A-0 594-218 and WO 94/10180, each fully incorporated herein by reference (as used herein unless otherwise stated "solution" refers to any mixture including suspensions ) Support Materials The support materials used in the methods of this invention are preferably porous paniculate materials, such as for example, talc, inorganic oxides, inorganic chlorides and resinous materials such as polyolefin or polymeric compounds The most preferred support materials are porous inorganic oxide materials, which include those from the Periodic Table of Elements of Groups 2, 3, 4, 5, 13 or 14 metal oxides Silica, alumina, silica-alumina, and mixtures thereof are particularly preferred. Other inorganic oxides that may be employed either alone or in combination with the silica, alumina or silica-alumina are magnesia, titania, zirconia, and the like. Preferably the support material is porous silica which has a surface area in the range of from 10 to 700 m /g, a total pore volume in the range of from 0 1 to 4 0 cc/g and an average particle diameter in the range of from 10 to 500 μm More preferably, the surface area is in the range of from 50 to 500 m /g, the pore volume is in the range of from 0.5 to 3.5 cc/g and the average particle diameter is in the range of from 20 to 200 μm Most preferably the surface area is in the range of from 100 to 400 m 2 /g, the pore volume is in the range of from 0.8 to 3.0 cc/g and the average particle diameter is in the range of from 30 to 100 μm. The average pore diameter of typical porous support materials is in the range of from 10 to lOOOA. Preferably, a support material is used that has an average pore diameter of from 50 to 500 A, and most preferably from 75 to 35θA. It may be particularly desirable to dehydrate the silica at a temperature of from 100°C to 800°C anywhere from 3 to 24 hours. Method for Preparing the Catalyst System The methods of this invention are distinguished by the use of an aliphatic hydrocarbon solvent during the preparation of the catalyst system. Surprisingly, the resulting catalyst systems have a markedly increased activity compared to conventionally prepared metallocene catalyst systems. Preferably, the ratio of the total volume of aliphatic hydrocarbon to aromatic hydrocarbon used to prepare the catalyst system is at least 1 :1, more preferably in the range of from 1 : 1 to 10: 1 or more, even more preferably from 2: 1 to 8:1, even more preferably from 3: 1 to 5: 1. Any aliphatic hydrocarbon or mixture of aliphatic hydrocarbons can be used in the methods of this invention. Preferably the aliphatic hydrocarbon is a 3-C10 alkane. More preferably the aliphatic hydrocarbon is selected from the group consisting of pentane, hexane, heptane, isopentane, cyclohexane, octane, isobutane, butane, and propane. Most preferably the aliphatic hydrocarbon is selected from the group consisting of: isopentane, pentane, hexane, heptane and isobutane. Alumoxane is typically dissolved in toluene as a 10% to 30 % solution. Preferably a 30% solution of alumoxane, preferably methylalumoxane, is used to minimize the volume of toluene. At higher alumoxane concentrations, gels tend to form. The metallocene and alumoxane may be independently contacted with the support with either the metallocene or the alumoxane contacted first or the three components may be mixed together at one time. Likewise the aliphatic hydrocarbon solvent may be independently contacted with the three components or with any combination of components. Thus the precipitation can occur either in the presence of the support, prior to contact with the support, or after one or more of the components are supported. Preferably, however, the metallocene and alumoxane are precontacted in an aromatic hydrocarbon solvent and their reaction product is mixed with the support. This is particularly preferred when the metallocene alone is either insoluble or sparingly soluble in both aliphatic and aromatic hydrocarbons. It is also preferable to contact the metallocene and alumoxane in solution, i.e., an aromatic hydrocarbon solution such as toluene. The aliphatic hydrocarbon is preferably mixed with the support material and the metallocene/alumoxane reaction product solution combined with the support at which point precipitation occurs. In an alternative embodiment the total amount of alumoxane used to activate the metallocene is split into two portions which are approximately equal. The first portion is reacted with the metallocene in solution to form a reaction product which is then mixed with a slurry of support material in aliphatic hydrocarbon. The second alumoxane portion is then added. Regardless of which of the above methods is used, once all of the catalyst components are combined, the mixture is easier to mix if a slurry is formed. To facilitate drying, however, it is preferable to use as little overall liquid as possible. Thus, when using porous support material, it is preferred that the total volume of liquid (both aromatic and aliphatic hydrocarbon) applied to the support is less than 5 times the total pore volume of the porous support, more preferably less than 4 times the total pore volume of the porous support and even more preferably less than 3 times the total pore volume of the porous support. Procedures for measuring the total pore volume of porous support are well known in the art. The preferred method is described in Volume 1, Experimental Methods in Catalyst Research, Academic Press, 1968, pages 67-96. In preferred embodiments, the metallocene and activator are precontacted and allowed to react in solution for a time period ranging from 1 minute to 16 hours, more preferably at least 10 minutes, and most preferably 10 minutes to 1 hour. Likewise, it is preferable to mix the metallocene/alumoxane reaction product with a hexane slurry of support material and allow the mixture to sit for at least 10 minutes, preferably 10 minutes to one hour. If the alumoxane is split into portions, then again, it is preferable to allow the second portion to react with the metallocene/alumoxane/support material mixture for at least 10 minutes, preferably 10 minutes to 1 hour. Once all of the components including the aliphatic hydrocarbon are combined, the catalyst system is preferably dried although the catalyst system can be used directly in polymerization. If the catalyst system is dried or allowed to dry, preferably little or no heat is used. The exact drying conditions will depend on the specific embodiment, the size of the catalyst batch, and the amount of liquid but in every instance it is preferable to use little or no heat for the least amount of time possible. A vacuum or purge of inert gas such as nitrogen may be used but, again, it is preferable to use these sparingly to avoid contamination and reduction in catalyst activity. The supported catalyst system may be used directly in polymerization or the catalyst system may be prepolymerized using methods well known in the art. For details regarding prepolymerization, see United States Patent Nos. 4,923,833 and 4,921,825, EP 0 279 863 and EP 0 354 893 each of which is fully incorporated herein by reference. In an alternative embodiment, the catalyst system is prepared using an olefin promoter as a metallocene reactant. This method has also has been found by the present inventor to lead to increased activity as described in copending U.S. Patent Application No. ("Improved Metallocene Catalyst Systems" filed on the same day as this application by the same inventor - fully incorporated herein by reference). Polymerization and Catalyst System Performance The catalyst system prepared by the methods of this invention may be used in the polymerization of any monomer and optionally comonomers in any process including gas, slurry or solution phase or high pressure autoclave processes. (As used herein, unless differentiated, "polymerization" includes copolymerization and "monomer" includes comonomer.) Preferably, a gas or slurry phase process is used, most preferably a bulk liquid propylene polymerization process is used. In the preferred embodiment, this invention is directed toward the bulk liquid polymerization and copolymerization of propylene or ethylene, particularly propylene, in a slurry or gas phase polymerization process, particularly a slurry polymerization process. Another embodiment involves copolymerization reactions of propylene or ethylene, particularly propylene, with one or more of the alpha- olefin monomers having from 4 to 20 carbon atoms, preferably 4-12 carbon atoms, for example alpha-olefin comonomers of ethylene, butene-1, pentene-1, 4- methylpentene-1, hexene-1, octene-1, decene-1, and cyclic olefins such as styrene, cyclopentene or norbornene. Other suitable monomers include polar vinyl, diolefins such as dienes, for example, 1,3-butadiene, 1 ,4-hexadiene, norbornadiene or vinylnorbornene, acetylene and aldehyde monomers. In another embodiment ethylene or propylene is polymerized with at least two different comonomers to form a terpolymer and the like, the preferred comonomers are a combination of alpha-olefin monomers having 3 to 10 carbon atoms, more preferably 3 to 8 carbon atoms, and/or dienes having 4 to 10 carbon atoms. Typically in a gas phase polymerization process a continuous cycle is employed where in one part of the cycle of a reactor, a cycling gas stream, otherwise known as a recycle stream or fluidizing medium, is heated in the reactor by the heat of polymerization. The recycle stream usually contains one or more monomers continuously cycled through a fluidized bed in the presence of a catalyst under reactive conditions. This heat is removed in another part of the cycle by a cooling system external to the reactor. The recycle stream is withdrawn from the fluidized bed and recycled back into the reactor. Simultaneously, polymer product is withdrawn from the reactor and new or fresh monomer is added to replace the polymerized monomer. (See for example U.S. Patent Nos. 4,543,399; 4,588,790; 5,028,670; 5,352,749; 5,405,922, and 5,436,304 all of which are fully incorporated herein by reference.) A slurry polymerization process generally uses pressures in the range of 1 to 500 atmospheres or even greater and temperatures in the range of -60°C to 280°C. In a slurry polymerization, a suspension of solid, paniculate polymer is formed in a liquid polymerization medium to which ethylene and comonomers and often hydrogen along with catalyst are added. The liquid employed in the polymerization medium can be, for example, an alkane or a cycloalkane. The medium employed should be liquid under the conditions of polymerization and relatively inert. Non-limiting examples of liquid mediums include hexane and isobutane. As shown below by the Examples, the catalyst systems of this invention exhibit markedly increased activity as compared to conventionally prepared supported metallocene catalyst systems. Any increase in activity is highly desirable particularly in commercial processes. The polymers and copolymers made by the catalyst systems of the invention are useful in forming operations such as, for example, film, sheet, and fiber extrusion and co-extrusion as well as blow molding, injection molding, sheet thermoforming and rotational molding. Films include blown or cast films in mono- layer or multilayer constructions formed by coextrusion or by lamination. Such films are useful as shrink film, cling film, stretch film, sealing films, oriented films, snack packaging, heavy duty bags, grocery sacks, baked and frozen food packaging, medical packaging, industrial liners, membranes, etc. in food-contact and non-food contact applications. Fiber forming operations include melt spinning, solution spinning and melt blown fiber operations. Such fibers may be used in woven or nonwoven form to make filters, diaper fabrics, medical garments, geotextiles, etc. Extruded articles include, for example, medical tubing, wire and cable coatings, geomembranes, and pond liners. Molded articles include single and multi-layered constructions in the form of bottles, tanks, large hollow articles, rigid food containers and toys, etc.. EXAMPLES Example 1 10 g of silica gel (Davison D-948, Average Particle Size, "APS", = 35 m, dried at 600°C) was charged into an 8 oz bottle equipped with a magnetic stirring bar. 40 ml of hexane was added into the bottle. Into a 4 oz. bottle equipped with a magnetic stirring bar, a 0.1 lg of rac-Me2Si(2-Me-4-phenylindenyl)2ZrCl2 and 5 ml methylalumoxane ("MAO") in toluene solution (30wt%) were charged. The mixture was stirred at ambient temperature for 10 minutes. The mixture was then transferred into the 8 oz bottle containing the silica gel and hexane slurry. This mixture was allowed to react at ambient temperature for 10 minutes. 6.4 ml of MAO in toluene (30wt%) was charged into the bottle and the mixture was allowed to react at ambient temperature for 10 minutes. At the end of the reaction, the mixture was dried by nitrogen purging at 40°C to 50°C. A free flowing solid was obtained at the end of the preparation. Into a clean 2-liter autoclave, a 0.3 ml of triethylaluminum in heptane (1.5 M) followed by 1 liter of liquid propylene were charged. The reactor was heated to 70°C. 100 mg of the catalyst prepared above was then charged into the autoclave through a catalyst injection tube. The catalyst was washed into the autoclave by 200 ml of liquid propylene. The total pressure inside the reactor was around 480 psig. The polymerization was allowed to proceed at 70°C for 1 hour. After the polymerization, the unreacted propylene was vented and the polymer slurry was transferred into an evaporation dish. The autoclave inside wall and agitator were very clean. A total of 294g of polymer was obtained. Example 2 Example 1 was repeated except that 0.2 g of rac- Mβ2Si(2-Me-4- phenylindenyl)2ZrCl2 was used in the prearation. A total of 187 g of polymer was obtained. Example 3 Examle 1 was repeated except that all 11.4 ml of MAO was mixed with the metallocene at the beginning and no subsequent MAO was added. A total of 199g of polymer was obtained. Example 4 Example 3 was repeated except that 0.2 g of rac- Mβ2Si(2-Me-4- phenylindenyl)2ZrCl2 was used int he preparation . A total of 169g of polymer was obtained. Example 5 (Comparative) 10 g of silica gel (Davison D-948, Average Particle Size, "APS", = 35 m, dried at 600°C) was charged into an 8 oz bottle equipped with a magnetic stirring bar. Into a 4 oz. bottle equipped with a magnetic stirring bar, a 0.1 lg of rac- Me2Si(2-Me-indenyl)2ZrCl2 and 11.4 ml methylalumoxane ("MAO") in toluene solution (30wt%) were charged. The mixture was stirred at ambient temperature for 10 minutes. 30 ml of toluene solvent was charged into the mixture and the mixture was then transferred into the 8 oz bottle containing the silica gel. This mixture was allowed to react at ambient temperature for 10 minutes. 6.4 ml of MAO in toluene (30wt%) was charged into the bottle and the mixture was allowed to react at ambient temperature for 10 minutes. At the end of the reaction, the mixture was dried by nitrogen purging at 40°C to 50°C. A free flowing solid was obtained at the end of the preparation. A total of 160 g of polymer was obtained following the polymerization proceedure of Example 1. Examle 6 10 g of silica gel (Davison D-948, Average Particle Size, "APS", = 35 m, dried at 600°C) was charged into an 8 oz bottle equipped with a magnetic stirring bar. 40 ml of hexane was charged into the bottle. Into a 4 oz. bottle equipped with a magnetic stirring bar, a 0.2g of rac-Me2Si(2-Me-4-phenylindenyl)2ZrCl2 and 11.4 ml methylalumoxane ("MAO") in toluene solution (30wt%) were charged. The mixture was stirred at ambient temperature for 10 minutes. The mixture was then transferred into the 8 oz bottle containing the silica gel and hexane slurry. This mixture was allowed to react at ambient temperature for 10 minutes. 0.5 ml of styrene (99%) was charged into the bottle and the mixture was allowed to react at ambient temperature for 10 minutes. At the end of the reaction, the mixture was dried by nitrogen purging at 40°C to 50°C. A free flowing solid was obtained at the end of the preparation. A total of 232 g of polymer was obtained following the polymerization proceedure of Example 1. Example 7 10 g of silica gel (Davison D-948, Average Particle Size, "APS", = 35 m, dried at 600°C) was charged into an 8 oz bottle equipped with a magnetic stirring bar. 40 ml ofhexane was added into the bottle. Into a 4 oz. bottle equipped with a magnetic stirring bar, a 0.2g of rac-Me2Si(2-Me-4-phenylindenyl)2ZrCl2 and 5 ml methylalumoxane ("MAO") in toluene solution (30wt%) were charged. The mixture was stirred at ambient temperature for 10 minutes. The mixture was then transferred into the 8 oz bottle containing the silica gel and hexane slurry. This mixture was allowed to react at ambient temperature for 10 minutes. 6.4 ml of MAO in toluene (30wt%) was charged into the bottle and the mixture was allowed to react at ambient temperature for 10 minutes. 0.5 ml of styrene (99%) was charged and the mixture was allowed to react at ambient temperature for 10 minutes. At the end of the reaction, the mixture was dried by nitrogen purging at 40°C to 50°C. A free flowing solid was obtained at the end of the preparation. A total of 240 g of polymer was obtained following the polymerization proceedure of Example 1. While the present invention has been described and illustrated by reference to particular embodiments, it will be appreciated by those of ordinary skill in the art that the invention lends itself to many different variations not illustrated herein. For these reasons, then, reference should be made solely to the appended claims for purposes of determining the true scope of the present invention. Although the appendant claims have single appendencies in accordance with U.S. patent practice, each of the features in any of the appendant claims can be combined with each of the features of other appendant claims or the main claim.

Claims: I claim: Claim 1. A method for forming a supported metallocene catalyst system comprising: (a) reacting one or more metallocenes and an alumoxane activator to form a catalyst solution; and (b) mixing the catalyst solution with support material in the presence of aliphatic hydrocarbon. Claim 2. A method for forming a supported metallocene catalyst system comprising: (a) reacting metallocene and an alumoxane activator to form a catalyst solution; (b) mixing aliphatic hydrocarbon with support material; and (c) combining the catalyst solution with the mixture. Claim 3. A method for forming a supported metallocene catalyst system comprising: (a) reacting metallocene and a first alumoxane portion to form a catalyst solution; (b) combining aliphatic hydrocarbon and support material to form a mixture; (c) combining the catalyst solution with the mixture; and then (d) adding a second activator portion. Claim 4. The method of any of the preceding cairns wherein the catalyst solution comprises aromatic hydrocarbon solvent and wherein the ratio of aliphatic hydrocarbon to aromatic hydrocarbon is at least 1 : 1. Claim 5. The method of any of the preceding claims wherein the metallocene is represented by the formula: wherein M is selected from the group consisting of titanium, zirconium, hafnium, vanadium niobium, tantalum, chromium, molybdenum and tungsten; R and R 2 are identical or different, are one of a hydrogen atom, a C\ - Cjo alkyl group, preferably a C1-C3 alkyl group, a C1-C10 alkoxy group, a C^- C10 aryl group, a ^-C\Q aryloxy group, a C2-C10 alkenyl group, a C2-C4 alkenyl group, a C7-C40 arylalkyl group, a C7-C40 alkylaryl group, a Cg-C4ø arylalkenyl group, or a halogen atom; R 3 and R are hydrogen atoms; R 5 and R^ are identical or different, and are one of a halogen atom, a C]- CJO alkyl group which may be halogenated, a Cg-Cio aryl group which may be halogenated, a C2-C]o alkenyl group, a C7-C40 -arylalkyl group, a C7-C40 alkylaryl group, a Cg-C4o arylalkenyl group, a -NR2 15 , -SR 15 , -OR 15 , -OSiR3 15 or -PR2 5 radical, wherein R 15 is one of a halogen atom, a C]-CI Q alkyl group, or a Cό-Cio aryl group; R 7 is R 1 R11 RU R11 M2 M2 M 2 M 2 (CR 2 13 )- R12 R12 R12 R1 R11 R11 R11 M2 M 2 R12 R12 R12 -B(R ! ] )-, -A1(R Ϊ i)-, -Ge-, -Sn-, -O-, -S-, -SO-, -SO 2 -, -N(R ! ϊ)-, -CO-, - P(R π >, or -P(O)(R π )-; wherein: R 1, R 2 and R 13 are identical or different and are a hydrogen atom, a halogen atom, a C1-C20 alkyl group, a C1-C20 fluoroalkyl group, a C6-C30 aryl group, a C6-C30 fluoroaryl group, a C1-C20 alkoxy group, a C2-C20 alkenyl group, a C7-C40 arylalkyl group, a C -C40 arylalkenyl group, a C7-C40 alkylaryl group, or R 1 and R 12 , or R 1 and R 3 , together with the atoms binding them, can form ring systems; M 2 is silicon, germanium or tin; R 8 and R 9 are identical or different and have the meanings stated for R !; m and n are identical or different and are zero, 1 or 2, m plus n being zero, 1 or 2; and the radicals R ^ are identical or different and have the meanings stated for R.1 R12 anjj R13 ^J two adjacent R 1 ^ radicals can be joined together to form a ring system. Claim 6. The method of any of the preceding claims wherein the aliphatic hydrocarbon is a C3 to C10 alkane. Claim 7. The method of any of the preceding claims further comprising the step of recovering dry supported metallocene catalyst system. Claim 8. The method of any of the preceding claims wherein the aliphatic hydrocarbon is isopentane or hexane, the support material is silica and the activator is methylalumoxane. Claim 9. The method of any of the preceding claims wherein the metallocene is selected from the group consisting of rac-: dimethylsilandiylbis(2-methylindenyl)zirconium dichloride; dimethylsilandiylbis(2,4-dimethylindenyl)zirconium dichloride; dimethylsilandiylbis(2,5,6-trimethylindenyl)zirconium dichloride; dimethylsilandiylbis indenyl zirconium dichloride; dimethylsilandiylbis(4, 5,6,7- tetrahydroindenyl)zirconium dichloride dimethylsilandiylbis(2-methyl-4,5-benzoindenyl)zirconium dichloride; dimethylsilandiylbis(2-methyl-4-phenylindenyl)zirconium dichloride; dimethylsilandiylbis(2-methyl-4,6-diisopropylindenyl)zirconium dichloride; dimethylsilandiylbis(2-methyl-4-napthylindenyl)zirconium dichloride; and dimethylsilandiylbis(2-ethyl-4-phenylindenyl)zirconium dichloride. 10. A metallocene catalyst system prepared by the method of any of the preceding claims.

Inventors: CHANG MAIN, CHANG, MAIN
Applicants: EXXON CHEMICAL PATENTS INC, EXXON CHEMICAL PATENTS INC.
Application year: 1997
Main classification: C08F4
IPC codes: C08F4, C08F10