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Title:
SUPPORTED OLEFIN POLYMERIZATION CATALYSTS AND THEIR USE IN POLYMERIZATION PROCESSES
Document Type and Number:
WIPO Patent Application WO/2008/045171
Kind Code:
A2
Abstract:
Supported catalyst systems and polymerization processes for making polyolefins with the supported catalyst systems are disclosed.

Inventors:
APECETCHE MARIA A (US)
AGAPIOU AGAPIOS K (US)
SCHOEB-WOLTERS ANN M (US)
CANN KEVIN J (US)
MOORHOUSE JOHN H (US)
GOODE MARK G (US)
Application Number:
PCT/US2007/019646
Publication Date:
April 17, 2008
Filing Date:
September 10, 2007
Export Citation:
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Assignee:
UNIVATION TECH LLC (US)
APECETCHE MARIA A (US)
AGAPIOU AGAPIOS K (US)
SCHOEB-WOLTERS ANN M (US)
CANN KEVIN J (US)
MOORHOUSE JOHN H (US)
GOODE MARK G (US)
International Classes:
C08F4/602
Foreign References:
US6828268B1
US6670302B2
US20040242811A1
Attorney, Agent or Firm:
ARECHEDERRA, Leandro, III et al. (LLC5555 San Felipe St., Suite 195, Houston TX, US)
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Claims:

CLAIMS

What is claimed is:

1. A composition, the composition comprising the contact product of: at least one catalyst compound, the at least one catalyst compound consisting essentially of a chromium containing catalyst; and at least one support, the at least one support having an average pore diameter of 185 Angstroms or greater (as measured by the BET method disclosed herein) and an average particle size in the range of from 1 to 50 microns.

2. The composition of claim 1, wherein the at least one support has an average pore diameter of 190 Angstroms or greater (as measured by the BET method disclosed herein).

3. The composition of claim 1, wherein the at least one support has an average pore diameter of 200 Angstroms or greater (as measured by the BET method disclosed herein).

4. The composition of claim 1, wherein the at least one support has an average pore diameter of 220 Angstroms or greater (as measured by the BET method disclosed herein).

5. The composition of any one of the preceding claims, wherein the at least one support has an average particle size in the range of from 15 to 45 microns.

6. The composition of any one of the preceding claims, wherein the at least one support has an average particle size in the range of from 20 to 42 microns.

7. The composition of any one of the preceding claims, wherein the at least one support has no more than 10% of the particles having a size less than 10

microns and no more than 10% of the particles having a size greater than 50 microns.

8. The composition of any one of claims 1-7, wherein the at least one support has no more than 10% of the particles have a size below 12 microns and no more than 8% of the particles have a size above 50 microns.

9. The composition of any one of the preceding claims, wherein the at least one support comprises talc, clay, silica, titania, alumina, magnesia, zirconia, iron oxides, boria, calcium oxide, zinc oxide, barium oxide, thoria, aluminum phosphate gel, polyvinylchloride, substituted polystyrene, polystyrene dtvinyl benzene pόlyolefins, graphite, or mixtures thereof.

10. The composition of any one of the preceding claims, wherein the at least one support comprises silica, titania, alumina, or mixtures thereof.

11. The composition of any one of the preceding claims, wherein the at least one support is heated prior to being contacted with the at least one catalyst compound.

12. The composition of any one of the preceding claims, wherein the at least one support is heated at a temperature of 300 0 C or greater prior to being contacted with the at least one catalyst compound.

13. The composition of any one of the preceding claims, wherein the contact product comprises at least 0.45 wt% chromium based upon the total weight of the contact product, optionally, at least 3.00 wt% titania, preferably, at least 3.50 wt% titania, based upon the total weight of the contact product.

14. The composition of any one of the preceding claims, wherein the at least one chromium containing catalyst is selected from the group consisting of chromium oxide, chromocene, silyl chromate, chromyl chloride (CrO 2 Cl 2 ),

chromium-2-ethyl-hexanoate, biscyclopentadienyl chromium(II), chromium(II) acetate, chromium(III) acetate, chromium(III) acetylacetonate, chromium(II) chloride, chromium(III) chloride, chromium(II) fluoride, chromium(III) fluoride, chromium hexacarbonyl, chromium(III) nitrate, chromium nitride, chromium(III) 2,4-pentanedionate, chromium(III) perchlorate, chromium(III) potassium sulfate, chromium(III) sulfate, chromium(III) telluride, and combinations thereof.

15. The composition of any one of claims 1-13, wherein the at least one chromium containing catalyst is chromium oxide.

16. The composition of any one of claims 1-13, wherein the at least one chromium containing catalyst is chromium acetate.

17. The composition of any one of the preceding claims, wherein the at least one chromium containing catalyst contains one or more chromium catalysts.

18. The composition of any one of claims 1-16, wherein the at least one chromium containing catalyst contains only chromium metal catalysts.

19. A polymerization process to produce polyolefins, the polymerization process comprising contacting the composition of any one of claims 1-18, in an activated form, with one or more olefins in a reactor.

20. The process of claim 19, wherein the at least one chromium containing catalyst is activated by heating at a temperature of from 500 0 C or more or 800 0 C or more, and optionally, reduced prior to being contacted with the one or more olefins.

21. The process of claim 20, wherein the at least one chromium containing catalyst is reduced with an organometallic compound.

22. The process of claim 21, wherein the organometallic compound is an aluminum alkyl.

23. The process of any one of claims 19-22, wherein the process is a gas phase polymerization process.

24. The process of claim 23, wherein the gas phase polymerization process further comprises at least one ccmdensing agent and is operated in condensed mode.

25. The process of any one of claims 19-24, wherein the reactor is a continuous fluidized bed stirred tank reactor.

26. The process of any one of claims 19-25, wherein the one or more olefins are selected from C 2 to Cg alpha-olefins or mixtures thereof.

27. The process of any one of claims 19-25, wherein the one or more olefins are selected from ethylene, butene, hexene, or mixtures thereof.

Description:

SUPPORTED OLEFIN POLYMERIZATION CATALYSTS AND THEIR USE IN POLYMERIZATION PROCESSES

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of Serial No. 60/851,029, filed

October 11, 2006, the disclosure of which is incorporated by reference in its entireity.

FIELD OF THE INVENTION

[0002] The invention relates generally to catalyst systems and processes for polyolefin production in gas-phase fluidized bed polymerization reactors and polyolefins manufactured therefrom.

BACKGROUND

[0003] The complexity of the polymerization process for polyolefin production yields a plethora of variables, any number of which can make a large impact on the process itself and/or the targeted product. Recent advances in supported catalyst systems, including their respective components, have provided for many process improvements such as improved catalyst productivities and/or the ability to produce many new polymers having improved properties useful in a wide variety of superior products and applications.

[0004] Among these catalyst systems are those including metallocene or metallocene-type catalysts systems and chromium containing catalysts systems. There has been a tremendous focus in the polyolefin industry on developing new and improved supported catalyst systems, to produce novel polymers, to improve operability of the reactor, and to obtain desirable catalyst productivity. One aspect of the supported catalyst system which is of growing interest is the support material itself. In particular, support materials are no longer viewed as inert carriers of the catalysts (and other, optional components) to the polymerization process as in the past.

[0005] For example, U.S. Application No. 11/192,935, filed July 29, 2005, to the same assignee of this application, discloses among other things supported catalyst compositions comprising an alkylalumoxane, a metallocene- alky 1 and an

inorganic oxide support having an average particle size of from 0.1 to 100 μm, preferably, from 1 to 60 μm, more preferably, from 1 to 50 μm, and calcined at a temperature of 600 0 C or greater.

[0006] U.S. Application No. 11/218,213, filed September 1, 2005, to the same assignee of this application, discloses among other things supported, multi- transition-metal catalyst compositions comprising: (a) at least two catalyst components selected from the group consisting of: a nonmetallocene catalyst component and a metallocene catalyst component; (b) a support material that has a D50 of less than 30 microns and a particle size distribution having a D 90 /D10 ratio of less than 6; and (c) an activator.

[0007] U.S. Application No. 11/441,505, filed May 26, 2006, to the same assignee of this application, discloses among other things processes for making polyolefins, the process comprising contacting, in a reactor, ethylene and at least one comonomer selected from the group consisting of C 3 to Cs alpha olefin in the presence of a supported catalyst system, the supported catalyst system comprising at least one titanium compound, at least one magnesium compound, at least one electron donor compound, at least one activator compound, and at least one silica support material, the at least one silica support material having a median particle size in the range of from 20 to 50 microns and an average pore diameter > 220 Angstroms; wherein the at least one silica support material has no more than 10% of the particles having a size less than 10 microns and no more than 10% of the particles having a size greater than 50 microns.

[0008] Other background references include WO 00/39173, WO

2003/022890, WO 02/04119, EP 0 808 849 Al, EP 0 931 796 Al, U.S. Patent Application Publication Nos. 2003/162917, 2004/167015, and 2005/0164875.

[0009] As these teachings demonstrate, not all support materials are the same or necessarily behave similarly in polymerization processes.

[0010] Accordingly, there exists a need for improved supported catalyst systems, especially in the areas of metallocene catalysts and chromium containing catalysts, as demonstrated, for example, through desirable catalyst productivities and/or enhanced reactor performance, and yet produce targeted products with

desirable polymer properties, such as, for example, as seen through the flow index of the resin produced.

SUMMARY OF INVENTION

[0011] The invention generally provides for a . composition, the composition comprising the contact product of: at least one catalyst compound, the at least one catalyst compound consisting essentially of a chromium containing catalyst; and . at least one support, the at least one support having an average pore diameter of 185 Angstroms or greater (as measured by the BET method disclosed herein) and an average particle size in the range of from 1 to 50 microns. [0012] The invention also generally provides for a polymerization process to produce polyolefins, the polymerization process comprising contacting the aforementioned composition, in an activated form, with one or more olefins in a reactor.

DETAILED DESCRIPTION

[0013] In a class of embodiments, the invention is directed to supported catalysts systems comprising metallocene or metallocene type catalysts and chromium containing catalysts and processes for polymerizing olefins using these supported catalyst systems. For example, embodiments described herein may be directed to the production of polyolefin polymers with desirable physical properties using high productivity catalysts using a porous particulate substrate, such as silica, having a particle size in a particular range and having a particular average pore diameter. In particular, for example, supported catalyst systems employing supports having a smaller average particle size and larger average pore diameter than systems of the prior art.

[0014] As described in more detail below, the supported catalyst system may comprise at least one catalyst and at least one support. The at least one catalyst may include a catalyst selected from the group consisting of at least one metallocene catalyst, at least one chromium containing catalyst, and combinations thereof. The supported catalyst system may also include at least one activator

along with a wide variety of other components such as scavengers and continuity additives discussed in more detail below. The supported catalyst systems may be used in polymerization processes for making polyolefin polymers. The polymerization process may include contacting, in a reactor, such as a continuous gas fluidized bed reactor, at least one class of monomers selected from the group consisting of C 2 to C 8 alpha-olefins, optionally with at least one comonomer, in the presence of the supported catalyst system.

[0015] As used herein, in reference to Periodic Table "Groups" of

Elements, the "new" numbering scheme for the Periodic Table Groups is used as shown in the CRC HANDBOOK OF CHEMISTRY AND PHYSICS (David R. Lide ed., CRC Press 81 st ed. 2000).

Catalyst

Metallocene Catalysts

[0016] The at least one metallocene catalyst or metllocene type catalyst

(used here interchangeably, unless otherwise specified) generally refers to a metal complex of a at least one metal and one or more ligands. The at least one metallocene catalyst may include "half sandwich" and "full sandwich" compounds having one or more Cp ligands (such as cyclopentadienyl and ligands isolobal to cyclopentadienyl) bound to at least one Group 3 to Group 12 metal atom, and one or more leaving groups bound to the at least one metal atom. In a class of embodiments, the at least one metallocene catalysts of are represented by the formula (I):

Cp A Cp B MX n (I) wherein M is a metal atom selected from the group consisting of Groups 3 through 12 atoms, such as a Group IV metal, and lanthanide Group atoms in another embodiment. In other embodiments, M may be selected from Ti, Zr, Hf atoms. In yet other embodiments, M is hafnium (Hf). Each leaving group X is chemically bonded to M; each Cp group is chemically bonded to M; and n is 0 or an integer from 1 to 4, and either 1 or 2 in a particular embodiment.

[0017] The Cp ligands are one or more rings or ring systems, at least a portion of which includes π-bonded systems, such as cycloalkadienyl ligands and heterocyclic analogues. The Cp ligands are distinct from the leaving groups bound to the catalyst compound in that they are not highly susceptible to substitution or abstraction reactions. The ligands represented by Cp A and Cp B in formula (I) may be the same or different cyclopentadienyl ligands or ligands isolobal to cyclopentadienyl, either or both of which may contain heteroatoms and either or both of which may be substituted with a group R. Non-limiting examples of substituent groups R include groups selected from hydrogen radicals, alkyls, alkenyls, alkynyls, cycloalkyls, aryls, acyls, aroyls, alkoxys, aryloxys, alkylthiols, dialkylamines, alkylamidos, alkoxycarbonyls, aryloxycarbonyls, carbomoyls, alkyl- and dialkyl-carbamoyls, acyloxys, acylaminos, aroylaminos, and combinations thereof. In one embodiment, Cp A and Cp B are independently selected from the group consisting of cyclopentadienyl, indenyl, tetrahydroindenyl, fluorenyl, and substituted derivatives of each. (As used herein, the term "substituted" means that the group following that term possesses at least one moiety in place of one or more hydrogens in any position, which moieties are selected from such groups as halogen radicals (e.g., Cl, F, Br), hydroxyl groups, carbonyl groups, carboxyl groups, amine groups, phosphine groups, alkoxy groups, phenyl groups, naphthyl groups, Cj to Cio alkyl groups, C 2 to CJ O alkenyl groups, and combinations thereof. Examples of substituted alkyls and aryls include, but are not limited to, acyl radicals, alkylamino radicals, alkoxy radicals, aryloxy radicals, alkylthio radicals, dialkylamino radicals, alkoxycarbonyl radicals, aryloxycarbonyl radicals, carbomoyl radicals, alkyl- and dialkyl- carbamoyl radicals, acyloxy radicals, acylamino radicals, arylamino radicals, and combinations thereof.)

[0018] hi one embodiment, each leaving group X in the formula (I) above may be independently selected from the group consisting of halogen ions, hydrides, Ci -I2 alkyls, C 2 - 12 alkenyls, Ce- I2 aryls, C 7-20 alkylaryls, Ci -J2 alkoxys, Cβ. 16 aryloxys, C 7-J g alkylaryloxys, C1.12 fluoroalkyls, CO -I 2 fluoroaryls, and Ci-I 2 heteroatom-containing hydrocarbons, and substituted derivatives thereof. As used

herein, the phrase "leaving group" refers to one or more chemical moieties bound to the metal center of the catalyst component, which can be abstracted from the catalyst component by an activator, thus producing a species active towards olefin polymerization or oligomerization.

[0019] The structure of the at least one metallocene catalyst may take on many structures, such as those disclosed in, for example, U.S. Pat. No. 5,026,798, U.S. Pat. No. 5,703,187 and U.S. Pat. No. 5,747,406, including a dimer or oligomeric structure, such as disclosed in, for example, U.S. Pat. No. 5,026,798 and U.S. Pat. No. 6,069,213. Others include those catalysts describe in published U.S. Pat. App. Nos. US20050124487A1, US20050137364A1, US20050164875A1, and US20050148744. Each of the aforementioned references is hereby incorporated by reference. In other embodiments, the at least one metallocene catalyst may be formed with a hafnium metal atom, such as is described in U.S. Pat. No. 6,242,545, which is hereby incorporated by reference. [0020] The metallocene catalysts components described above include their structural or optical or enantiomeric isomers (racemic mixture), and, in one embodiment, may be a pure enantiomer. As used herein, a single, bridged, asymmetrically substituted metallocene catalyst component having a racemic and/or meso isomer does not, itself, constitute at least two different bridged, metallocene catalyst components.

[0021] In one embodiment, the metallocene catalyst contains hafnium as the metal atom. In other embodiments, at least one of the ligands (pi-bonded moieties) contains a cyclopentadienyl group. In other embodiments, the metallocene contains a chloride leaving group. In yet other embodiments, the metallocene contains a fluoride leaving group. In yet other embodiments, the metallocene contains a methyl leaving group.

[0022] In some embodiments, the metallocene catalyst may include dimethylsilyl(tetramethylcyclopentadienyl)(cyclopropylamido) titanium X n , dimethyls ilyl(tetramethyleyclopentadienyl)(cyclobutylamido)titanium X n , dimethylsilyl(tetramethyleyclopentadienyl)(cyclopentylamido) titanium X n , dimethylsilyl(tetramethylcyclopentadienyl)(cyclohexylamido)t itanium X n , dimethylsilyl(tetramethylcyclopentadienyl)(cycloheptylamido) titanium X n ,

dimethylsilyl(tetramethylcyclopentadienyl)(cyclooctylamido)t itanium X n , dimethylsilyl(tetramethylcyclopentadieπyl)(cyclononylamido) titanium X n , dimethylsilyl(tetramethylcyclopentadienyl)(cyclodecylamido)t itanium X n , dimethylsilyl(tetramethylcyclopentadienyl)(cycloundecylamido )titanium X n , dimethylsilyl(tetramethylcyclopen.tadienyl)(cyclododecylaini do)titanium X n , dimethylsilyl(tetramethylcyclopentadienyl)(sec-butylamido)ti tanium X n , dimethylsilyl(tetxamethylcyclopentadienyl)(n-octylamido)tita nium X n , dimethylsilyl(tetramethylcyclopentadienyl)(n-decylamido)tita nium X n , dimethylsilyl(tetxamethylcyclopentadienyl)(n-octadecylamido) titanium X n , methylphenylsilyl(tetramethylcyclopentadienyl)(cyclopropylam ido)titanium X n , methylphenylsilyl(tetramethylcyclopentadienyl)(cyclobutylami do)titanium X n , methylphenylsilyl(tetramethylcyclopentadienyl)(cyclopentylam ido)titanium X n , methylphenylsilyl(tetramethylcyclopentadienyl)(cyclohexylami do)titanium X n , methylphenylsilyl(tetramethylcyclopentadienyl)(cycloheptylam ido)titanium X n , methylphenylsilyl(tetramethylcyclopentadienyl)(cyclooctylami do)titanium X n , methylphenylsilyl(tetramethylcyclopentadienyl)(cyclononylami do)titanium X n , methylphenylsilyl(tetramethylcyclopentadienyl)(cyclodecylami do)titanium, X n , methylphenylsilyl(tetramethylcyclopentadienyl)(cycloundecyla mido)titanium X n , methylphenylsilyl(tetramethylcyclopentadienyl)(cyclododecyla mido)titanium X n , methylphenylsilyl(tetramethylcyclopentadienyl)(sec-butylamid o)titanium X n , methylphenylsilyl(tetramethylcyclopentadienyl)(n-octylamido) titanium X n , methylphenylsilyl(tetramethylcyclopentadienyl)(n-decylamido) titanium X n , methylphenylsilyl(tetramethylcyclopentadienyl)(n-octadecylam ido)titanium X n , diphenylsilyl(tetramethylcyclopentadienyl)(cyclopropylamido) titanium X n , diphenylsilyl(tetramethylcyclopentadienyl)(cyclobutylamido)t itanium X n , diphenylsilyl(tetramethylcyclopentadienyl)(cyclopentylamido) titanium X n , diphenylsilyl(tetramethylcyclopentadienyl)(cyclohexylamido)t itaniura X n , diphenylsilyl(tetramethylcyclopentadienyl)(cycloheptylamido) titanium X n , diphenylsilyl(tetramethylcyclopentadienyl)(cyclooctylamido)t itanium X n , diphenylsilyl(tetramethylcyclopentadienyl)(cyclononylamido)t itanium X n , diphenylsilyl(tetramethylcyclopentadienyl)(cyclodecylamido)t itanium X n , diphenylsilyl(tetramethylcyclopentadienyl)(cycloundecylamido )titanium X n ,

diphenylsilyl(tetramethylcyclopentadienyl)(cyclododecylamido )titanium X n , diphenylsilyl(tetramethylcyclopentadienyl)(sec-butylamido)ti tanium X n , diph.enylsilyl(tetramethyleyclopentadienyl)(n-octylamido)tit anium X n , diphenylsilyl(tetramethyleyclopentadienyl)(n-decylamido)tita nium X n , diphenylsilyl(tetramethylcyclopentadienyl)(n-octadecylamido) titanium X n , and derivatives thereof.

[0023] In other embodiments, the metallocene catalyst may include cyclopentadienylzirconium X n , indenylzirconium X n , (l-methylindenyl)zirconium X n , (2-methylindenyl)zirconium X n , (l-propylindenyl)zirconium X n , (2- propylindenyl)zirconium X n , (l-butylindenyl)zirconium X n , (2- butylindenyl)zirconium X n , (metiiylcyclopentadienyl)zirconium X n , tetrahydroindenylzirconium X n , (pentamethylcyclopentadieny^zirconium X n , cyclopentadienylzirconium X n , pentamethylcyclopentadienyltitanium X n , tetramethylcyclopentyltitanium X n , 1,2,4-trimethylcycloρentadienylzirconium X n , dimethylsilyl(l,2,3,4-tetramethylcyclopentadienyl)(cyclopent adienyl)zirconium X n , dimethylsilyl(l,2,3,4-tetramethylcyclopentadienyl)(l,2,3- trimethylcyclopentadienyl)zirconium X n , dimethylsilyl(l,2,3,4- tetramethylcyclopentadienyl)(l,2-dimethylcyclopentadienyl)zi rconium X n , dimethylsilyl(l,2,3,4-tetramethyl-cyclopentadienyl)(2- methylcyclopentadienyl)zirconium X n , dimethylsilyKcyclopentadienylXindenylJzirconium X n , dimethylsilyl(2- methylindenyl)(fluorenyl)zirconium X n , diphenylsilyl( 1,2,3 ,4-tetramethyl- cyclopentadienyl)(3-propylcyclopentadienyl)zirconium X n , dimethylsilyl(l ,2,3,4- tetramethylcyclopentadienyl) (S-t-butylcyclopentadienytyzirconium X n , dimethylgermyl( 1 ,2-dimethylcyclopentadienyl)(3 - isopropylcyclopentadienyOzirconium X n , dimethylsilyl(l ,2,3 ,4-tetramethyl- cyclopentadienyl)(3-methylcycloρe- ntadienyl)zirconium X n , diphenylmethylidene^cyclopentadienylXP-fluorenyOzirconium X n , diphenylmethylidene(cyclopentadienyl)(indenyl)zirconium X n , isopropylidenebis(cyclopentadienyl)zirconium X n , isopropylidene(cyclopentadienyl)(9-fluorenyl)zirconium X n , isopropylidene(3- methylcyclopentadienyl)(9-fluorenyl)zirconium X n , ethylenebis(9-

fluorenyl)zirconium X n , meso-ethylenebis(l-indenyl)zirconium X n , ethylenebis(l- indenyl)zirconium X n , ethylenebis(2-methyl-l-indenyl)zirconium X n , ethylenebis(2-methyl-4,5,6,7-tetrahydro-l-indenyl)zirconium X n , ethylenebis(2- propyl-4,5,6,7-tetrahydro-l-indenyl)zirconium X n , ethylenebis(2-isopropyl- 4,5 ,6,7-tetrahydro- 1 -indenyl)ziτconium X n , ethylenebis(2-butyl-4,5 ,6,7- tetrahydro- 1 -indenyl)zirconium X n , ethylenebis(2-isobutyl-4,5 ,6,7-tetrahydro- 1- indenyl)zirconium X n , dimethylsilyl(4,5,6,7-tetrahydro-l-indenyl)zirconium X n , diphenyl(4,5,6,7-tetrahydro-l -indenyl)zirconium X n , ethylenebis(4,5,6,7- tetrahydro- 1 -indenyl)zirconium X n , dimethylsilylbis(cyclopentadienyl)zirconium X n , dimethylsilylbis(9-fluorenyl)zirconiura X n , dimethylsilylbis(l- indenyl)zirconium X n , dimethylsilylbis(2-methylindenyl)zirconium X n , dimethylsilylbisCl-propylindeny^zirconium X n , dimethylsilylbis(2- butylindenyl)zirconium. X n , diphenylsilylbis(2-methylindenyl)zirconium X n , diphenylsilylbis(2-propylindenyl)zirconium X n , diphenylsilylbis(2- butylindenyl)zirconium X n , dimethylgermylbis(2-mediylindeήyl)zirconium X n , dimethylsilylbis(tetrahydroindenyl)zircomurn X n , dimethylsilylbis(tetramethylcyclopeπtadienyl)zirconium X n , dimethylsilyl(cyclopentadienyl)(9-fluorenyl)zirconium X n , diphenylsilyl(cyclopentadienyl)(9-fluorenyl)zirconium X n , diphenylsilylbis(indenyl)zirconium X n , cyclotrimeth.ylenesilyl(tetramethylcyclopentadienyl)(cyclope ntadienyl)zirconium

Xn j cyclotetramethylenesilyl(tetramethylcyclopentadienyl)(cyclop entadienyl)zirconiu m v X n , . cyclotrimethylenesilyl(tetramethylcyclopentadienyl)(2- mefliylindenyl)zirconiuni X n , cyclotrimethylenesilyl(tetramethylcyclopentadienyl)(3- methylcyclopentadienyl)zirconium X n , cyclotrimethylenesilylbis(2- methylindenyl)zirconium ' X n , cyclotrimethylenesilyl(tetramethylcyclopentadienyl)(2,3,5- trimethylcyclopentadienyl)zirconium X n , cyclotrimethylenesilylbis(tetramethylcyclopentadienyl)zircon ium X n , and derivatives thereof.

[0024] In some embodiments, the metallocene catalyst may be a bis(n- propylcyclopentadienyl)hafnium X n , bis(n-butylcyclopentadienyl)hafnium X n , bis(n-pentylcyclopentadienyl)hafnium X n , (n-propyl cyclopentadienyl)(n- butylcyclopentadienyl)hafnium X n , bis[(2- trimethylsilylethyl)cyclopentadienyl]hafnium X n , bis(trimethylsilyl cyclopentadienyl)hafnium X n , dimethylsilylbisCn-propylcyclopentadienyOhafnium X n , dimethylsilylbisCn-butylcyclopentadienyOhafnium X n , bis(l-n-propyl-2- methylcyclopentadienyl)hafnium X n , (n-propylcyclopentadienyl)(l-n-propyl-3-n- butylcyclopentadienyl)hafnium X n , or combinations thereof, where X n is as described above. In other embodiments, the metallocene catalyst may be a bis(n- propylcyclopentadienyl)hafhium dichloride, a bis(n- propylcyclopentadienyl)hafnium difluoride, or a dimethyl bis(n- propylcyclopentadienyl)hafnium.

[0025] In other embodiments, the metallocene catalyst may include bis(l,3-methyl-n-butylcyclopentadienyl)zirconium X n , bis(n- propylcyclopentadienyl)zirconium ' X n , dimethylsilylbis(tetrahydroindenyl)zirconium X n , and combinations thereof.

Activators

[0026] The supported catalyst system may comprise at least one activator, or the catalyst system may be contacted with at least one activator. The term "activator," as used here, is defined to be any compound or component which can activate at least one metallocene catalyst as described above, for example, such as an organσmetallic compound, an alumoxane (or aluminoxane), a modified alumoxane (or modified aluminoxane), a Lewis acid, a non-coordinating ionic activator or ionizing activator, and any other compound that can convert a neutral metallocene catalyst component to a metallocene cation, and any combinatioin thereof. For example, an alumoxane or a modified alumoxane may be used alone or in combination with using ionizing activators, neutral or ionic, such as tri (n- butyl) ammonium tetrakis(pentafluorophenyl) boron or a trisperfluorophenyl boron metalloid precursor, in countless combinations of preparing the activated supported catalyst system. In particular, methylaluminoxane ("MAO") or

modified methyl aluminoxane ("MMAO") may be contacted with at least one support, optionally, with the catalyst or contacted apart from the catalyst, such as described by Gregory G. Hlatky, Heterogeneous Single-Site Catalysts for Olefin Polymerization, 100(4) CHEMICAL REVIEWS 1347-1374 (2000). [0027] There are a variety of methods for preparing aluminoxane and modified aluminoxanes, non-limiting examples of which are described in U.S. Pat. Nos. 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 and European publications EP-A-O 561 476, EP-Bl-O 279 586 and EP-A-O 594-218, and PCT publication WO 94/10180.

[0028] Ionizing compounds may contain an active proton, or some other cation associated with but not coordinated or only loosely coordinated to the remaining ion of the ionizing compound. Such compounds and the like are described in European publications EP-A-O 570 982, EP-A-O 520 732, EP-A-O 495 375, EP-A-O 426 637, EP-A-500 944, EP-A-O 277 003 and EP-A-O 277 004, and U.S. Pat. Nos. 5,153,157, 5,198,401, 5,066,741, 5,206,197, 5,241,025, 5,387,568, 5,384,299 and 5,502,124 and U.S. Patent Application Ser. No. 08/285,380, filed Aug. 3, 1994, now abandoned. Combinations of activators are also contemplated by the invention, for example, aluminoxanes and ionizing activators in combinations, see for example, PCT publications WO 94/07928 and WO 95/14044 and U.S. Pat. Nos. 5,153,157 and 5,453,410.

Chromium Containing Catalyst

[0029] The at least one chromium containing catalyst, a large class of them commonly referred to as Phillips-type catalysts, suitable for use in the supported catalyst systems described herein include, but are not limited to CrO 3 (chromium oxide), Cr 2 Oa (chromium(HI) oxide), chromocene, silyl chromate, chromyl chloride (CrO 2 CIa), chromium-2-ethyl-hexanoate, chromium acetylacetonate (Cr(AcAc) 3 ), and the like. Non-limiting examples are disclosed in U.S. Pat. Nosí 3,709,853, 3,709,954, 3,231,550, 3,242,099, 4,077,904, and 4,855,370. In other embodiments, the supported chromium-based catalyst

systems described herein may include any compound of chromium which is oxidizable to CrO 3 under the activation conditions employed. [0030] Other non-limiting examples of the chromium catalyst compounds may include a diarene chromium compound, biscyclopentadienyl chromium(II), chromium(II) acetate, chromium(III) acetate, chromium(III) acetylacetonate, chromium(II) chloride, chromium(III) chloride, chromium(II) fluoride, chroniium(III) fluoride, chromium hexacarbonyl, chromiurή(III) nitrate, chromium nitride, chromium(III) 2,4-pentanedionate, chromium(III) perchlorate, chromium(III) potassium sulfate, chromium(III) sulfate, and chromium(III) telluride, among others. In other embodiments, the chromium catalyst compound may include bis(cyclopentadienyl)chromium X n , where X n is as described above. [0031] Chromium compounds may also include, for example, those disclosed in U.S. Patent App. Publication Nos. 2001/004663, 2001/0044507, 2002/0028891, 2003/0125593, 2004/0087745, and U.S. Patent No. 6,989,344. [0032] In a class of embodiments, the supported catalyst system may consist essentially of any of the above listed or referenced chromium containing catalysts. As used here, "consists essentially of and "consisting essentially of" excludes the bimetallic catalyst systems described, for example, in U.S. Serial No. 11/218,213, but does not exclude the presence of other steps, elements, components (such as cocatalysts or additives), or other materials that may be used in the productions of polyolefins, including other mixed catalyst systems, including one or more chromium containing catalysts, additionally, they do not exclude impurities normally associated with the elements and materials used. For example, in a class of embodiments, the at least one chromium containing catalyst contains one or more chromium catalysts. In yet another class of embodiments, the at least one chromium containing catalyst contains only chromium metal catalysts.

Activator and Activation

[0033] The at least one chromium containing catalyst may be activated by any suitable means. Commonly, the at least one chromium containing catalyst is activated by physical processes, such as by heating. Optionally, the at least one

chromium containing catalyst may further be reduced prior to being introduced into the polymerization reactor, such as with an organometallic compound, such as an aluminum alkyl, or a boron containing compound.

[0034] For example, catalyst manufacturers generally prepare the catalysts, often by placing the chromium on a solid support, such as alumina or silica, as discussed in more detail below. Without being bound to theory, it is believed that the support helps to stabilize the activity of the chromium and allows the catalyst to be shipped in an inactive form to the purchaser. Once the catalyst arrives at a polymer manufacturing site, it must be activated for use in the polymerization process. Typical commercial activation processes consist of activating chromium catalysts by calcining or heating large quantities of the catalyst in dry air, for example, but may be in the presence of other gases as well, either alone or in mixtures, such as oxygen. Activation is performed in some type of activation apparatus or vessel such as a fluidized bed activator. This procedure may involve activation temperatures in the range of 400-1,000 0 C, such as 500 0 C or more, or alternatively, 800 0 C or more. The ramp up may be conducted slowly over a period of many hours and then the temperature may be maintained typically for another several hours.

[0035] Optionally, the at least one chromium containing catalyst may further be reduced prior to being introduced into the polymerization reactor, such as with an organometallic compound, such as an aluminum alkyl or a boron containing compound. Examples include trialkyl aluminums, such as triethyl aluminum and triisobutyl aluminum, alkyl aluminum halides, alkyl aluminum alkoxides, dialkyl zincs, dialkyl magnesiums, and borohydrides including those of the alkali metals, especially sodium, lithium and potassium, and aluminum. Other examples include alkyl boranes such as triethyl borane, triisobutyl borane, and trimethyl borane and hydrides of boron such as diborane, pentaborane, hexaborane and decaborane. The use of such materials with chromium' containing catalysts is within the skill in the art.

Supports and Methods for Supporting

[0036] The supported catalyst system comprises at least one support. The terms "support," "support material," or "carrier," as used herein, are used interchangeably and refer to any support material, such as, for example, inorganic or organic support materials. Supports described herein may be used with any of the embodiments described above and optionally, with other components.

[0037] Supports, methods of supporting, modifying, and activating supports for metallocene catalysts are discussed in, for example, 1 METALLOCENE-BASED POLYOLEFINS 173-218 (J. Scheirs & W. Kaminsky eds., John Wiley & Sons, Ltd. 2000). Many of the same principles as disclosed therein are applicable to supported catalysts systems containing chromium. Methodology and equipment used to support catalysts are well known to those skilled in the art. The supported catalyst system of the invention can be made and used in a variety of different ways.. Examples of supporting the catalyst used in the invention are described in U.S. Pat. Nos. 4,701,432, 4,808,561, 4,912,075, 4,925,821, 4,937,217, 5,008,228, 5,238,892, 5,240,894, 5,332,706, 5,346,925, 5,422,325, 5,466,649, 5,466,766, 5,468,702, 5,529,965, 5,554,704, 5,629,253, 5,639,835, 5,625,015, 5,643,847, 5,665,665, 5,468,702, and 6,090,740 and PCT publications WO 95/32995, WO 95/14044, WO 96/06187, and WO 97/02297. An additional, specific method for producing a supported catalyst system may be fond in U.S. Application Ser. Nos. 08/265,533, filed Jun. 24, 1994, now abandoned and 08/265,532, filed Jun. 24, 1994, now abandoned, and PCT publications WO 96/00245 and WO 96/00243, both published Jan. 4, 1996.

[0038] In a class of embodiments, the support material may be a porous support material. Non-limiting examples of support materials include inorganic oxides and inorganic chlorides, and in particular such materials as talc, clay, silica, alumina, magnesia, zirconia, iron oxides, boria, calcium oxide, zinc oxide, barium oxide, thoria, aluminum phosphate gel, and polymers such as polyvinylchloride and substituted polystyrene, functionalized or crosslinked organic supports such as polystyrene divinyl benzene polyolefins or polymeric compounds, and mixtures thereof, and graphite, in any of its various forms.

[0039] Desirable inorganic oxides include, but are not limited to, Group 2,

3, 4, 5, 13, and 14 oxides and chlorides. Support materials include silica, alumina, silica-alumina, magnesium chloride, graphite, and mixtures thereof in one embodiment. Other useful supports include magnesia, titania, zirconia, montmorillonite (as described in, for example, EP 5 116 65 Bl), phyllosilicate, and the like. In other embodiments, combinations of the support materials may be used, including, but not limited to, combinations such as silica-chromium, silica- alumina, silica-titania, and the like. Additional support materials may include those porous acrylic polymers described in EP0767184B1.

[0040] In a class of embodiments, the at least one support may have an average particle size distribution by Malvern analysis (Malvern Instruments, Ltd., of Worcestershire, UK) within the range from 0.1 to 100 microns; and from 1 to 80 microns in other embodiments. In other embodiments, the support may have an average particle size in the range of from 10 to 50 microns; from 15 to 45 microns in other embodiments; and from 20 to 40 microns in yet other embodiments. Alternatively stated, the at least one support may have an average particle size distribution of 60 microns or less, 55 microns or less, 50 microns or less, 45 microns or less, or 40 microns or less.

[0041] In another class of embodiments, the at least one support may have a D 50 of less than about 30 microns and a particle size distribution having a D90/D10 ratio of less than about 6. As used herein, the term "Dio" is understood to mean that 10% of the particles in a sample of a support material have a diameter smaller than the Dio value. The term "D50" will be understood to mean the median particle size value. The term "D9 0 " will be understood to mean that 90% of the particles in the sample have a diameter smaller than the D90 value. The Dio, Dso, and D 90 values for a sample support material may be calculated with the use of a conventional, commercially-available particle size analyzer. An example of a suitable particle size analyzer is commercially available from Malvern Instruments, Ltd., of Worcestershire, UK, under the trade name Mastersizer S long bench. An example of suitable software that may be used with the aforementioned particle size analyzer is commercially available from Malvern and referred to as Mastersizer Series Software Version 2.19. The use of a Malvern

particle size analyzer to generate Dio, D50, and D90 values for a particular sample is described in a Malvern manual titled "Getting Started, MAN 0101, Issue 1.3 (August 1997)," particularly at page 7.6, the disclosure of which is hereby incorporated by reference.

[0042] In certain other embodiments, the support materials of the present invention have a D 90 /D 10 ratio of less than about 5, and in certain embodiments, less than about 4.5. In certain embodiments, the support materials of the present invention has a D 90 of less than about 60 microns, and in certain embodiments a D 90 of less than about 55 microns, and in certain embodiments a D9 0 of less than about 50 microns, and in certain embodiments a D 90 of less than about 45 microns. In certain embodiments, the support materials of the present invention have a D 50 of less than about 30 microns, and in certain embodiments a D5 0 of less than about 25 microns. In certain embodiments, the support materials of the present invention have a Dio of less than about 5 microns, and in certain embodiments a Djo of less than about 8 microns, and in certain embodiments a Dio of less than about 10 microns.

[0043] In a particular embodiment, the at least one support may comprise a synthetic amorphous silicon dioxide having a pore volume ranging from 1.5 to 2.0 cnrVg and a surface area of from 280 to 350 m 2 /g, with a D 90 of about 44 micron, a D 50 of about 25 micron, and a Dio of about 10 micron, commercially available from INEOS, Joliet, IL, USA, under the trade name ES-757. In particular, ES-757 may also have the following properties.

TABLE 1

[0044] In yet other embodiments, for example, the at least one support may have a particle size distribution by Malvern analysis in which no more than 10 percent of the particles have a size below 5 microns; below 8 microns in other embodiments; below 10 microns in other embodiments; below 12 microns in other embodiments; and below 15 microns in yet other embodiments. In other embodiments, the support may have a particle size distribution in which no more than 10 percent of the particles have a size greater than 50 microns; greater than 45 microns in other embodiments; greater than 40 microns in other embodiments; greater than 35 microns in other embodiments; and greater than 30 microns in yet other embodiments. In some embodiments, no more than 8 percent of the particles are above or below the above stated dimensions; no more than 5 percent in other embodiments; and no more than 3 percent in yet other embodiments. [0045] In any of the embodiments described herein, the at least one support may have an average pore diameter of 185 Angstroms or greater; an average pore diameter of 190 Angstroms or greater; an average pore diameter of 195 Angstroms or greater; an average pore diameter of 200 Angstroms or greater; an average pore diameter of 220 Angstroms or greater; alternatively, an average pore diameter of 225 Angstroms or greater; alternatively, an average pore diameter of 230 Angstroms or greater; alternatively, an average pore diameter of 235 Angstroms or greater; alternatively, an average pore diameter of 240 Angstroms or greater; alternatively, an average pore diameter of 245 Angstroms or greater; alternatively, an average pore diameter of 250 Angstroms or greater; alternatively, an average pore diameter of 255 Angstroms or greater; alternatively, an average pore diameter of 260 Angstroms or greater; and, alternatively, an average pore diameter of 265 Angstroms or greater, as measured by the BET method described in more detail below.

[0046] In other embodiments, the at least one support may have a surface area of greater than or equal to 200 square meters per gram, greater than or equal to 250 square meters per gram in other embodiments; greater than or equal to 300 square meters per gram in other embodiments; and greater than or equal to 350 square meters per gram in other embodiments. In yet other embodiments, the upper limit of the surface area may be 300 or less square meters per gram.

[0047] In any of the above, the support may have a particle size dispersity of less than 20 percent. In other embodiments, the support may have a particle size dispersity of less than 10 percent; less than 5 percent (monodisperse) in yet other embodiments.

[0048] In any of the above, the at least one support may have a support span, such as a silica span, of 1.0 or less.

[0049] In some embodiments, the improved catalysts described herein including these supports may have a productivity (as based on a mass balance) that is at least 3,000 grams polymer per gram of catalyst per hour; that is at least 4,500 grams polymer per gram of catalyst per hour in other embodiments; that is at least 6,000 grams polymer per gram of catalyst per hour in other embodiments; that is at least 7,000 grams polymer per gram of catalyst per hour in other embodiments; and that is at least 9,000 grams polymer per gram of catalyst per hour in yet other embodiments.

[0050] Alternatively stated, the productivity (as based on a mass balance) may be > 6,500 (g polymer), e.g., polyethylene/(g precursor); alternatively, > 7,000 (g polymer), e.g., polyethylene/(g precursor); alternatively, > 7,250 (g polymer), e.g., polyethylene/(g precursor); alternatively, > 7,500 (g polymer), e.g., polyethylene/(g precursor); alternatively, > 8,000 (g polymer), e.g., polyethylene/(g precursor); alternatively, > 8,500 (g polymer), e.g., polyethylene/(g precursor); and alternatively, > 9,000 (g polymer), e.g., polyethylene/(g precursor).

[0051] In any of the above, the settled bulk density of the polymer, e.g., polyethylene, may be at least 344.4 kilograms per cubic meter (21.5 pounds per cubic foot); at least 360.4 kilograms per cubic meter (22.5 pounds per cubic foot) in other embodiments; at least 376.4 kilograms per cubic meter (23.5 pounds per cubic foot) in other embodiments; and at least 384.4 kilograms per cubic meter (24.0 pounds per cubic foot) in yet other embodiments.

[0052] The at least one support as described above may be calcined.

Dehydrator or "calcining" apparatuses and their use are well known in the art. In one embodiment, the support is calcined at temperatures ranging from 500 0 C or greater, alternatively, from 600 0 C or greater, and alternatively, from 600 0 C to

1500 0 C in another embodiment; and from 650 0 C to 1200 0 C in yet another embodiment; and from 600 0 C to 1000 0 C in yet another embodiment; and from 700 0 C to 950 0 C in yet another embodiment; and from 750 0 C to 950 0 C in yet a more particular embodiment, and from 750 0 C to 900 0 C in yet a more particular embodiment, wherein a desirable range comprises any combination of any upper temperature limit with any lower temperature limit. In one embodiment, calcining takes place in the absence of oxygen and/or moisture by using, for example, an atmosphere of dry nitrogen. In another embodiment, calcining is done in the presence of oxygen or air (oxygen/nitrogen and optionally carbon dioxide). One skilled in the art recognizes where each would be appropriate for the various catalyst systems disclosed herein.

[0053] In any of the embodiments above, the at least one support may comprise a polymer bound ligand as described in U.S. Pat. No. 5,473,202, and/or the at least one functionalized support as described in, for example, European publication EP-A-0802203 or U.S. Pat. No. 5,688,880.

[0054] In any of the embodiments described above, the supported catalyst system of the invention may include at least one antistatic agent or one surface modifier or continuity additive or antifoulant agent, for example, those described in U.S. Pat. No. 5,283,278 and PCT publication WO 96/11960, and/or at least one scavenger.

[0055] When the at least one support as described above is incorporated into a supported catalyst system, the supported catalyst system may be spray dried as described, for example, in U.S. Pat. No. 5,648,310.

Polymerization Process

[0056] The polymerization process of the present invention may be carried out using any suitable process, such as, for example, solution, slurry, high pressure, and gas phase. A particularly desirable method for producing polyolefin polymers according to the present invention is a gas phase polymerization process preferably utilizing a fluidized bed reactor. This type reactor, and means for operating the reactor, are well known and completely described in, for example, U.S. Pat. Nos. 3,709,853; 4,003,712; 4,011,382; 4,302,566; 4,405,495; 4,543,399;

4,882,400; 5,352,749; 5,541,270; EP-A-O 802 202 and Belgian Patent No. 839,380. These patents disclose gas phase polymerization processes wherein the polymerization medium is either mechanically agitated or fluidized by the continuous flow of the gaseous monomer and diluent.

[0057] Other gas phase processes contemplated by the process of the invention include series or multistage polymerization processes. Also gas phase processes contemplated by the invention include those described in U.S. Pat. Nos. 5,627,242, 5,665,818 and 5,677,375, and European publications EP-A-O 794 200 EP-Bl-O 649 992, EP-A-O 802 202 and EP-B-634 421 all of which are herein fully incorporated by reference.

[0058] In general, the polymerization process of the present invention may be a continuous gas phase process, such as a fluid bed process. A fluid bed reactor for use in the process of the present invention typically has a reaction zone and a so-called velocity reduction zone. The reaction zone includes a bed of growing polymer particles, formed polymer particles and a minor amount of catalyst particles fluidized by the continuous flow of the gaseous monomer and diluent to remove heat of polymerization through the reaction zone. Optionally, some of the recirculated gases may be cooled and compressed to form liquids that increase the heat removal capacity of the circulating gas stream when readmitted to the reaction zone. A suitable rate of gas flow may be readily determined by simple experiment. Makeup of gaseous monomer to the circulating gas stream is at a rate equal to the rate at which particulate polymer product and monomer associated therewith is withdrawn from the reactor, and the composition of the gas passing through the reactor is adjusted to maintain an essentially steady state gaseous composition within the reaction zone. The gas leaving the reaction zone is passed to the velocity reduction zone where entrained particles are removed. Finer entrained particles and dust may be removed in a cyclone and/or fine filter. The gas is passed through a heat exchanger wherein the heat of polymerization is removed, compressed in a compressor and then returned to the reaction zone. [0059] The process of the present invention is suitable for the production of homopolymers of olefins, including ethylene, and/or copolymers, terpolymers, and the like, of olefins, including polymers comprising ethylene and at least one

or more other olefins. The olefins may be alpha-olefins. The olefins, for example, may contain from 2 to 16 carbon atoms in one embodiment; ethylene and a comonomer comprising from 3 to 12 carbon atoms in another embodiment; ethylene and a comonomer comprising from 4 to 10 carbon atoms in another embodiment; and ethylene and a comonomer comprising from 4 to 8 carbon atoms in another embodiment.

[0060] In embodiments, polyethylenes may be prepared by the process of the present invention. Such polyethylenes may include hσmopolymers of ethylene and interpolymers of ethylene and at least one alpha-olefin wherein the ethylene content is at least about 50% by weight of the total monomers involved. Olefins that may be used herein include ethylene, propylene, 1-butene, 1-pentene, 1- hexene, 1-heptene, 1-octene, 4-methylpent-l-ene, 1-decene, 1-dodecene, 1- hexadecene and the like. Also usable are polyenes such as 1,3-hexadiene, 1,4- hexadiene, cyclopentadiene, dicyclopentadiene, 4-vinylcyclohex-l-ene, 1,5- cyclooctadiene, 5-vinylidene-2-norbornene and 5-vinyl-2-norbornene, and olefins formed in situ in the polymerization medium. When olefins are formed in situ in the polymerization medium, the formation of polyolefins containing long chain branching may occur.

[0061] Other monomers useful in the process described herein include ethylenically unsaturated monomers, diolefins having 4 to 18 carbon atoms, conjugated or non-conjugated dienes, polyenes, vinyl monomers and cyclic olefins. Non-limiting monomers useful in the invention may include norbornene, norbornadiene, isobutylene, isoprene, vinylbenzocyclobutane, styrenes, alkyl substituted styrene, ethylidene norbornene, dicyclopentadiene and cyclopentene. In another embodiment of the process described herein, ethylene or propylene may be polymerized with at least two different comonomers, optionally one of which may be a diene, to form a teηpolymer.

[0062] In one embodiment, the content of the alpha-olefin incorporated into the copolymer may be no greater than 30 mole percent in total; from 3 to 20 mole percent in other embodiments. The term "polyethylene" when used herein is used generically to refer to any or all of the polymers comprising ethylene described above.

[0063] Hydrogen gas is often used in olefin polymerization to control the final properties of the polyolefin. Using the catalyst system of the present invention, it is known that increasing the concentration (partial pressure) of hydrogen may increase the melt flow index (MFI) and/or melt index (MI) of the polyolefin generated. The MFI or MI can thus be influenced by the hydrogen concentration. The amount of hydrogen in the polymerization can be expressed as a mole ratio relative to " the total polymerizable monomer, for example, ethylene, or a blend of ethylene and hexene or propylene. The amount of hydrogen used in the polymerization processes of the present invention is an amount necessary to achieve the desired MFI or MI of the final polyolefin resin.

[0064] Further, it is common to use a staged reactor employing two or more reactors in series, wherein one reactor may produce, for example, a high molecular weight component and another reactor may produce a low molecular weight component. In one embodiment of the invention, the polyolefin is produced using a staged gas phase reactor. Such commercial polymerization systems are described in, for example, 2 METALLOCENE-BASED POLYOLEFINS 366-378 (John Scheirs & W. Kaminsky, eds. John Wiley & Sons, Ltd. 2000); U.S. Pat. No. 5,665,818, U.S. Pat. No. 5,677,375, and EP-A-O 794 200.

[0065] m one embodiment, the one or more reactors in a gas phase or fluidized bed. polymerization process may have a pressure ranging from about 0.7 to about 70 bar (about 10 to 1000 psia); and in another embodiment a pressure ranging from about 14 to about 42 bar (about 200 to about 600 psia). hi one embodiment, the one or more reactors may have a temperature ranging from about 10 0 C to about 150 0 C; and in another embodiment from about 40 0 C to about 125 0 C. In one embodiment, the reactor temperature may be operated at the highest feasible temperature taking into account the sintering temperature of the polymer within the reactor. In one embodiment, the superficial gas velocity in the one or more reactors may range from about 0.2 to 1.1 meters/second (0.7 to 3.5 feet/second); and from about 0.3 to 0.8 meters/second (1.0 to 2.7 feet/second) in another embodiment.

[0066] In one embodiment of the invention, the polymerization process is a continuous gas phase process that includes the steps of: (a) introducing a recycle stream (including ethylene and alpha olefin monomers) into the reactor; (b) introducing the supported catalyst system; (c) withdrawing the recycle stream from the reactor; (d) cooling the recycle stream; (e) introducing into the reactor additional monomer(s) to replace the monomer(s) polymerized; (f) reintroducing the recycle stream or a portion thereof into the reactor; and (g) withdrawing a polymer product from the reactor.

[0067] In embodiments of the invention, one or more olefins, C 2 to C 30 olefins or alpha-olefins, including ethylene or propylene or combinations thereof, may be prepolymerized in the presence of the metallocene catalyst systems described above prior to the main polymerization. The prepolymerization may be carried out batch-wise 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. Pat. 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 all of which are herein fully incorporated by reference. [0068] The present invention is not limited to any specific type of fluidized or gas phase polymerization reaction and can be carried out in a single reactor or multiple reactors such as two or more reactors in series. In embodiments, the present invention may be carried out in fluidized bed polymerizations (that may be mechanically stirred and/or gas fluidized), or with those utilizing a gas phase, similar to that as described above. In addition to well- known conventional gas phase polymerization processes, it is within the scope of the present invention that "condensing mode", including the "induced condensing mode" and "liquid monomer" operation of a gas phase polymerization may be used.

[0069] Embodiments of the present invention may employ a condensing mode polymerization, such as those disclosed in U.S. Patent Nos. 4,543,399; 4,588,790; 4,994,534; 5,352,749; 5,462,999; and 6,489,408, each of which is

hereby incorporated by reference. Condensing mode processes may be used to achieve higher cooling capacities and, hence, higher reactor productivity. In addition to condensable fluids of the polymerization process itself, other condensable fluids inert to the polymerization may be introduced to induce a condensing mode operation, such as by the processes described in U.S. Patent No. 5,436,304, which is hereby incorporated by reference.

[0070] Other embodiments of the preset invention may also use a liquid monomer polymerization mode such as those disclosed in U.S. Patent No. 5,453,471; U.S. Serial No. 08/510,375; PCT 95/09826 (US) and PCT 95/09827 (US). When operating in the liquid monomer mode, liquid can be present throughout the entire polymer bed provided that the liquid monomer present in the bed is adsorbed on or in solid particulate matter present in the bed, such as polymer being produced or inert particulate material (e.g., carbon black, silica, clay, talc, and mixtures thereof), so long as there is no substantial amount of free liquid monomer present. Operating in a liquid monomer mode may also make it possible to produce polymers in a gas phase reactor using monomers having condensation temperatures much higher than the temperatures at which conventional polyolefins are produced.

[0071] In one embodiment, a useful polymerization technique may be particle form polymerization or a slurry process where the temperature is kept below the temperature at which the polymer goes into solution. Other slurry processes include those employing a loop reactor and those utilizing a plurality of stirred reactors in series, parallel, or combinations thereof. Non-limiting examples of slurry processes include continuous loop or stirred tank processes. Also, other examples of slurry processes are described in U.S. Pat. Nos. 4,613,484 and 2 METALLOCENE-BASED POLYOLEFINS 322-332 (2000). [0072] In one embodiment, a slurry polymerization process generally uses pressures in the range of from 1 to 50 bar and even greater, and temperatures in the range of 0 0 C to 120 0 C. In a slurry polymerization, a suspension of solid, particulate polymer is formed in a liquid polymerization diluent medium to which ethylene and comonomers and often hydrogen along with catalyst are added. The suspension, including diluent, is intermittently or continuously removed from the

reactor where the volatile components are separated from the polymer and recycled, optionally after a distillation, to the reactor. The liquid diluent employed in the polymerization medium is typically an alkane having from 3 to 7 carbon atoms; in one embodiment, the alkane may be a branched alkane. The medium employed should be liquid under the conditions of polymerization and relatively inert. When a propane medium is used, the process must be operated above the reaction diluent critical temperature and pressure. In one embodiment, a hexane or an isobutane medium is employed.

[0073] In one embodiment of the process of the invention, the slurry or gas phase process may be operated in the presence of a metallocene-type catalyst system 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. By "essentially free," it is meant that these compounds are not deliberately added to the reactor or any reactor components, and if present, are present in the reactor at less than 1 ppm.

[0074] As noted above, the polymerization process of the present invention may be carried out by using a solution process. Non-limiting examples of solution processes are described in, for example, U.S. Pat. Nos. 4,271,060, 5,001,205, 5,236,998, and 5,589,555.

[0075] In another embodiment, one or all of the catalysts are combined with up to 15 weight percent of. a metal-fatty acid compound, such as, for example, an aluminum stearate, based upon the weight of the catalyst system (or its components), such as disclosed in, for example, U.S. Pat. Nos. 6,300,436 and 5,283,278. Other suitable metals include other Group 2 and Group 5-13 metals. In another embodiment, a solution of the metal-fatty acid compound is fed into the reactor. In another embodiment, the metal-fatty acid compound is mixed with the catalyst and fed into the reactor separately. These agents may be mixed with the catalyst or may be fed into the reactor in a solution or slurry with or without the catalyst system or its components.

Polymer

[0076] The polyolefins of the present invention may be blended with other polymers and/or additives to form compositions that can then be used in articles of manufacture. Those additives include antioxidants, nucleating agents, acid scavengers, plasticizers, stabilizers, anticorrosion agents, blowing agents, ultraviolet light absorbers, quenchers, antistatic agents, slip agents, pigments, dyes and fillers, and cure agents such as peroxides. These and other common additives in the polyolefin industry may be present in polyolefin compositions from 0.01 to 50 weight percent in one embodiment, and from 0.1 to 20 weight percent in another embodiment, and from 1 to 5 weight percent in yet another embodiment, wherein a desirable range may include any combination of any upper weight percent limit with any lower weight percent limit. Antioxidants and stabilizers such as organic phosphites, hindered amines, and phenolic antioxidants may be present in the polyolefin compositions of the invention from 0.001 to 5 weight percent in one embodiment, from 0.01 to 0.8 weight percent in another embodiment, and from 0.02 to 0.5 weight percent in yet another embodiment. [0077] Fillers may be present from 0.1 to 50 weight percent in one embodiment, and from 0.1 to 25 weight percent of the composition in another embodiment, and from 0.2 to 10 weight percent in yet another embodiment. Desirable fillers include, but are not limited to, titanium dioxide, silicon carbide, silica (and ouier oxides of silica, precipitated or not), antimony oxide, lead carbonate, zinc white, lithopone, zircon, corundum, spinel, apatite, barium sulfate, magnesiter, carbon black, dolomite, calcium carbonate, talc and hydrotalcite compounds of the ions Mg, Ca, or Zn with Al, Cr or Fe and CO 3 and/or HPO 4 , hydrated or not; quartz powder, hydrochloric magnesium carbonate, glass fibers, clays, alumina, and other metal oxides and carbonates, metal hydroxides, chrome, phosphorous and brominated flame retardants, antimony trioxide, silica, silicone, and blends thereof. These fillers may particularly include any other fillers and porous fillers and supports known in the art.

[0078] Fatty acid salts may also be present in the polyolefin compositions of the present invention. Such salts may be present from 0.001 to 2 weight percent of the composition in one embodiment, and from 0.01 to 1 weight percent in

another embodiment. Examples of fatty acid metal salts include lauric acid, stearic acid, succinic acid, stearyl lactic acid, lactic acid, phthalic acid, benzoic acid, hydroxystearic acid, ricinoleic acid, naphthenic acid, oleic acid, palmitic acid, and erucic acid, suitable metals including Li, Na, Mg, Ca, Sr, Ba, Zn, Cd, Al, Sn, Pb and so forth. Desirable fatty acid salts are selected from magnesium stearate, calcium stearate, sodium stearate, zinc stearate, calcium oleate, zinc oleate, and magnesium oleate.

[0079] With respect to the physical process of producing the blend of polyolefin and one or more additives, sufficient mixing should take place to assure that a uniform blend will be produced prior to conversion into a finished product. The polyolefin suitable for use in the present invention can be in any physical form when used to blend with the one or more additives. In one embodiment, reactor granules (defined as the granules of polymer that are isolated from the polymerization reactor) are used to blend with the additives. The reactor granules have an average diameter of from 10 microns to 5 mm; from 50 microns to 10 mm in another embodiment. Alternately, the polyolefin is in the form of pellets, such as, for example, pellets having an average diameter of from 1 mm to 6 mm that are formed from melt extrusion of the reactor granules.

[0080] One method of blending the additives with the polyolefin is to contact the components in a tumbler or other physical blending means, the polyolefin being in the form of reactor granules. This can then be followed, if desired, by melt blending in an extruder. Another method of blending the components is to melt blend the polyolefin pellets with the additives directly in an extruder, BRABENDER ® or any other melt blending means. [0081] The resultant polyolefin and polyolefin compositions of the present invention may be further processed by any suitable means such as by calendering, casting, coating, compounding, extrusion, foaming; all forms of molding including compression molding, injection molding, blow molding, rotational molding (rotomolding), and transfer molding; film blowing or casting and all methods of film formation to achieve, for example, uniaxial or biaxial orientation; thermoforming, as well as by lamination, pultrusion, protrusion, draw reduction, spinbonding, melt spinning, melt blowing, and other forms of fiber and nonwoven

fabric formation, and combinations thereof. These and other forms of suitable processing techniques are described in, for example, PLASTICS PROCESSING (Radian Corporation, Noyes Data Corp. 1986).

[0082] In the case of injection molding of various articles, simple solid state blends of the pellets serve equally as well as pelletized melt state blends of raw polymer granules, of granules with pellets, or of pellets of the two components, since the forming process includes a remelting and mixing of the raw material. In the process of compression molding of medical devices, however, little mixing of the melt components occurs, and a pelletized melt blend would be preferred over simple solid state blends of the constituent pellets and/or granules. Those skilled in the art will be able to determine the appropriate procedure for blending of the polymers to balance the need for intimate mixing of the component ingredients with die desire for process economy. [0083] The polymers produced may further contain additives such as slip, antiblock, antioxidants, pigments, fillers, antifog, UV stabilizers, antistats, polymer processing aids, neutralizers, lubricants, surfactants, pigments, dyes and nucleating agents. Preferred additives include silicon dioxide, synthetic silica, titanium dioxide, polydimethylsiloxane, calcium carbonate, metal stearates, calcium stearate, zinc stearate, talc, BaSC«4, diatomaceous earth, wax, carbon black, flame retarding additives, low molecular weight resins, hydrocarbon resins, glass beads and the like. The additives may be present in the typically effective amounts well known in the art, such as 0.001 weight % to 10 weight %. [0084] The polymers of the present invention have a bulk density measured in accordance with ASTM-D-1238 that, in one embodiment, may be greater than at least 0.30 grams per cubic centimeter. In another embodiment, the bulk density of the polymers may be in the range of 0.30 to 0.50 grams per cubic centimeter. In yet other embodiments, the bulk density may be greater than 0.50 grams per cubic centimeter.

[0085] The polyolefins then can be made into films, molded articles, sheets, wire and cable coating and the like. The films may be formed by any of the conventional technique known in the art including extrusion, co-extrusion, lamination, blowing and casting. The film may be obtained by the flat film or

tubular process which may be followed by orientation in a uniaxial direction or in two mutually perpendicular directions in the plane of the film to the same or different extents. Orientation may be to the same extent in both directions or may be to different extents. Particularly preferred methods to form the polymers into films include extrusion or coextrusion on a blown or cast film line. [0086] Common rheological properties, processing methods and end use applications of metallocene based polyolefins are discussed in, for example, 2 METALLOCENE-BASED POLYOLEFINS 400-554 (John Scheirs & W. Kaminsky, eds. John Wiley & Sons, Ltd. 2000). The polyolefin compositions of the present invention are suitable for such articles as films, fibers and nonwoven fabrics, extruded articles and molded. Examples of films include blown or cast films formed by coextrusion or by lamination 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, agricultural films and sheets. Examples of fibers include melt spinning, solution spinning and melt blown fiber operations for use in woven or non-woven form to make filters, diaper fabrics, hygiene products, medical garments, geotextiles, etc. Examples of extruded articles include tubing, medical tubing, wire and cable coatings, pipe, geomembranes, and pond liners. Examples of molded articles include single and multi-layered constructions in the form of bottles, tanks, large hollow articles, rigid food containers and toys, etc.

[0087] Other desirable articles that can be made from and/or incorporate the polyolefins of the present invention include automotive components, sporting equipment, outdoor furniture (e.g., garden furniture) and playground equipment, boat and water craft components, and other such articles. More particularly, automotive components include such as bumpers, grills, trim parts, dashboards and instrument panels, exterior door and hood components, spoiler, wind screen, hub caps, mirror housing, body panel, protective side molding, and other interior and external components associated with automobiles, trucks, boats, and other vehicles.

[0088] Further useful articles and goods may be formed economically or incorporate the polyolefms produced by the practice of our invention including: crates, containers, packaging material, labware, office floor mats, instrumentation sample holders and sample windows; liquid storage containers for medical uses such as bags, pouches, and bottles for storage and IV infusion of blood or solutions; wrapping or containing food preserved by irradiation, other medical devices including infusion kits, catheters, and respiratory therapy, as well as packaging materials for medical devices and food which may be irradiated by gamma or ultraviolet radiation including trays, as well as stored liquid, particularly water, milk, or juice, containers including unit servings and bulk storage containers.

[0089] It is to be understood that while the invention has been described in conjunction with the specific embodiments thereof, the foregoing description is intended to illustrate and not limit the scope of the invention. Other aspects, advantages and modifications will be apparent to those skilled in the art to which the invention pertains.

[0090] • Therefore, the following examples are put forth so as to provide those skilled in the art with a complete disclosure and description of how to make and use the compounds of the invention, and are not intended to limit the scope of that which the inventors regard as their invention.

EXAMPLES

EXAMPLE 1 Support Characterization

[0091] For laboratory-prepared precursors, silicas first were dehydrated under nitrogen flow in a laboratory Carbolite Vertical Furnace, Model No. VST 12/32/400/ 2408 CP-FM supplied by Carbolite, Inc., provided with a quartz glass tube of 3.0 cm outer diameter and 70 cm in total length, and two thermocouples. One thermocouple was placed in a thermowell within the quartz glass tube, while the other was affixed to the skin of the quartz glass tube by placing it between the two folding halves of the furnace, then clamping the folding halves shut. The

thermocouples were hooked up to a Nomad OM-SP1700 data logger supplied by Omega Engineering. A collection flask for excess blowout silica was attached at the top of the tube, which in turn was attached to a bubbler via a glass elbow.

[0092] About 25-30 grams of silica was poured via a funnel into the quartz glass tube to fill the tube about 2/3 full within the heating zone. A preset program was started to begin the dehydration, using a Eurotherm 2408 Programmable Temperature Controller. A typical ramp and soak profile may be found in U.S. Serial No. 11/441,505, Figure 2. The gas flow (in this case nitrogen) was preset to about 50 -100 cubic centimeters per minute.

[0093] At the end of the dehydration cycle (typically overnight), the silica was discharged into a clean, dry, N 2 -purged bottle and maintained in an inert atmosphere. The data logger information was downloaded to a computer file.

[0094] Three different silicas, (DAVISON-955™ silica (comparative), screened DAVISON-955™ silica (comparative), and INEOS ES-757™ silica (inventive). Certain properties of these silicas are presented in the Tables 2 and 3 below. The screened Davison-955 silica consisted of the fraction of Davison 955 silica that passed through a 325 mesh (44 μm) screen.

TABLE 2

Summary of B.E.T. Surface Area and Pore Volume of various samples of DAVISON silicas 955 and INEOS ES757 Silicas

TABLE 3

Summary of Pore Size by B.E.T. of various samples of DAVISON silicas 955 and

INEOS ES757 Silicas

[0095] The nitrogen adsorption/desorption analysis was performed on a

Micromeritics Accelerated Surface Area & Porosimetry instrument (ASAP 2405). The silica samples were out-gassed overnight at 200 0 C while under vacuum prior to analysis to remove any physisorbed species (i.e., moisture) from the sample's surface. Approximately 0.5 gram of sample was used for the analysis.

[0096] Typically, the BET method or B.E.T. surface areas, corresponding to the methodology developed by Brunauer, Emmett, and Teller, are achieved with a precision of <3% relative standard deviation (RSD). The instrument employs a static (volumetric) method of dosing samples and measures the quantity of gas (nitrogen) that can be physically adsorbed (physisorbed) on a solid at liquid nitrogen temperature. For the multi-point B.E.T. measurement, the volume of nitrogen uptake was measured at 5 pre-selected relative pressure points (0.06, 0.08, 0.12, 0.16, and 0.20) at constant temperature. The relative pressure is the ratio of the applied nitrogen pressure to the vapor pressure of nitrogen at the analysis temperature of 77 K. Pore sizes >~3,000 A diameter (>0.30 μm) are not detected by this method but can be detected with mercury porosimetry.

[0097] Test conditions for the nitrogen adsorption/desorption isotherms include 15 second equilibration interval, 97-point pressure table (40 adsorption points, 40 desorption points, 5-point B.E.T. surface area, 15 micropore points, and 1-point total pore volume), 2.5%/2.5 mmHg P/Po tolerance, and 120 min Po interval.

[0098] The B.E.T. surface area, pore volume, and pore size results include surface area and porosimetry data for pore sizes up to ~3,000 angstroms diameter for the silica samples. The adsorption and desorption results includes pore sizes between -17-3,000 A diameter, -0.0017-0.3 μm. A single point TPV was input at P/Po 0.995.

[0099] There was complete closure of desorption curve with the adsorption curve for the silica samples. However, differences in results in adsorption vs. desorption data can occur and is largely because desorption process behaves differently than the adsorption process. Typically, an adsorbate gas (nitrogen) will desorb much slower than when it condenses to fill a material's pores.

[0100] Generally, desorption branch of an isotherm is used to relate the amount of adsorbate lost in a desorption step to the average size of pores emptied in the step. A pore loses its condensed liquid adsorbate, known as the core of the pore, at a particular relative pressure related to the core radius by the Kelvin equation. After the core is evaporated, a layer of adsorbate remains on the wall of the pore. The thickness of this adsorbed layer is calculated for a particular relative pressure from the thickness equation. This layer becomes thinner with successive decreases in pressure, so that the measured quantity of gas desorbed in a step is composed of a quantity equivalent to the liquid cores evaporated in that step plus the quantity desorbed from the pore walls of pores whose cores have evaporated in that and previous steps. Barrett, Joyner, and Halenda [Barrett, E.P., Joyner, L.G., Halenda, P.P., J. Am Chem. Soc. 1951 73 373-380.] developed the method (known as the BJH method) which incorporates these ideas.

[0101] A pore filled with condensed liquid nitrogen has 3 zones:

The core - evaporates all at once when the critical pressure for that radius is reached; the relationship between the core radius and the critical pressure is defined by the Kelvin equation. The adsorbed layer - composed of adsorbed gas that is stripped off a bit at a time with each pressure step; the relationship between the thickness of the layer and the relative pressure is defined by the thickness

equation. The walls of the cylindrical pore itself - the diameter of the empty pore is required to determine the pore volume and area. End area is neglected. [0102] The recommendation for using either adsorption or desorption data is to use the adsorption data instead of the desorption data for comparing results between samples. Typically, the adsorption process is very clean for BJH calculations. The desorption process of N 2 out of bottle-shaped pores can not usually distinguish what fraction of pores is open vs. closed (some open-ended vs. some closed-ended pores).

[0103] In general, the BET surface area, single point total pore volume

(TPV), and average pore diameter (4V/A by BET) is best to use for comparing sample data since it also would include any micropore data <~17 A diameter but not <~4-5 A diameter. However, the adsorption data can also be used for comparing sample data but is limited to surface area and porosimetry analysis between -17 and ~3,000 A diameter.

[0104] The hydroxyl content of the three silicas dehydrated at 600 0 C was characterized by titration with TiCU in a hexane solution. After washing and drying of the treated silica, the titanium content of the treated silica (a measure of the presence of hydroxyl groups in the silica) was determined by a spectrophotometric method. The hydroxyi content of the three silicas is reported in the table below. The hydroxyl content was determined by TiCl 4 titration that binds to the surface OH-groups. The final titanium content, measured by a spectrophotometric method, is an indication of the OH-group content at a given dehydration temperature of the silica.

TABLE 4

TABLE 5

MALVERN Particle Size Distribution of various samples of DAVISON silicas 955 and

INEOS ES757 Silicas

[0105] The particle size distribution was measured with accuracy ± 1 % on the D(0.5) in the size range 0.020 -2000.000 microns. Measurements were made in n-heptane dispersion at room temperature using Hydro 2000S, small volume general-purpose automated sample dispersion unit.

[0106] Values of silicas particle size distribution are given in Table 6, where D(0.5) refers to the particle size in micron at which 50 w% of the sample is below that value, D(0.1) and D(0.9) respectively, 10 and 90 w% of the sample below.

[0107] Span is a measure of particle size distribution = [D(0.9)-

D(0.1)]/D(0.5).

TABLE 6

Particle Size Distribution of various samples of DAVISON silicas 955 and INEOS ES-757 Silicas Determined by MALVERN Analysis

[0108] Davison-955 silica has higher surface area and comparable pore volume than Ineos-ES757 silica. However, Ineos-ES757 silica has larger average pore diameter and smaller average particle size and narrower particle size distribution than Davison-955 silica.

EXAMPLE 2

Activator Disposed on Support Materials

[0109] About 9.5 grams of each of the three types of silica was placed in an oven-dried, air-free 100 mL Schlenk flask having a stir bar and rubber septum, tb which about 50 ml of dry, degassed hexane and 3 mL of triethylaluminum (TEAL) heptane solution (1.54 M) were added. Each of the three mixtures was stirred for about 30 minutes in an oil bath at 40 0 C, after which point the oil bath temperature was raised to 70 0 C and vacuum dried to complete dryness. The

resulting mixtures may be referred to as laboratory TEAL-on-silica (laboratory TOS).

EXAMPLE 3 Preparation of the Supported Catalyst System

[0110] Preparation of the supported catalyst system containing chromium oxide and titanium oxide on silica used in Polymerization Examples below consisted of three distinct steps. The first and third steps were performed in a fluidized bed catalyst activator. The second step was performed in an agitated mixing vessel. The starting raw materials were chromium (III) acetate on various silicas, including INEOS ES-757 silica in Catalyst Sample D. The chromium acetate content was such that the chromium loading was approximately 0.5 wt% as shown in the table below. Chromium acetate on silica was charged to the activator, fluidized with dry nitrogen, heated to 150°C for 4 hours, then cooled. The dried Cr on silica support was then charged to the agitated mixing vessel and to this was added isopentane. The contents were mixed and heating to 55°C was begun. For each pound of dried chromium on silica, 0.204 liters of a 65 wt% solution of tetraisopropyltitanate in isopentane was added. The contents were mixed for 2 to 2.5 hours at 53 to 56°C. The jacket was then heated to 100 0 C and the pressure lowered near atmospheric under which conditions the isopentane was evaporated off. The dried mixture of chromium and titanium compounds, on silica was transferred into the activator vessel, fluidized with dry nitrogen and heated at no more than 100°C/hr to 325°C. The bed was fluidized at 325°C for 2 hours, then the fluidizing gas was switched to dry air and the temperature increased at 50 0 C per hour to 825°C where it was held for 6 hours. The bed was then cooled to 300 0 C where the fluidizing gas was switched to dry nitrogen for the remainder of the cooldown. Samples of the resulting chromium catalyst were analyzed for wt% total chromium. The results are given in Table 7. For more specific examples and other supported catalyst system preparation methods see also U.S. Patent No. 6,989,344, col. 10, line 34, bridging, col. 14, line 28.

[Olll] The method for the preparation of the supported catalyst system as described above was repeated for Catalyst Samples A, B, C, D and E used in the following examples as reported in the Table 7.

TABLE 7

Catalyst Samples

EXAMPLE 4 Polymerization Process

[0112] The supported catalyst examples as prepared in EXAMPLE 3 were used in accordance with the gas phase fluid bed polymerization process as described in U.S. Patent No. 6,989,344, col. 27, line 35, spanning to col. 35, line 54. Additionally, the particular reaction conditions may be found in Table 8.

TABLE 8

[0113] As observed, the polymerizations were conducted during a period of impurity breakthrough that affected catalyst productivity and polymer flow index. Guard beds on feedstreams to the reactor typically remove such impurities

or prevent impurities from entering the reactor resulting in concentrations that do not generally effect the catalyst's behavior. However, in this case, the impurity could not be isolated even though the guard beds were regenerated or replaced with fresh material. However, it was found that the productivity of the catalyst and the FI could be restored by increasing the level of tri-ethyl aluminum (TEAL) added continuously to the reactor from its usual low level in the range of about 0.01 to 0.5 ppmw, more typically about 0.1 to 0.3 ppmw, on a weight basis in the resin, to the concentrations shown in Table 8. Increasing the TEAL, increased the catalyst productivity and reduced the polymer flow index. The tests were performed without the addition of oxygen to the reactor. Usually about 0.130 ppmv oxygen is required to produce the target 24 FI with the Davison 957 based catalyst in Examples A and E. This, therefore, provides a measure of the degree that the polymerization was altered by the unknown impurity. There was also an apparent baseline shift in the impurity level that is seen in the change in the FI for Example A and E, a decrease in FI from 23.8 to 18.6 dg/min. as shown in Table 9. The evaluation of the INEOS silicas in Examples B, C and D were made during this time of changing impurity level.

[0114] Nevertheless, supported catalyst systems employing the INEOS silica exhibited desirable catalyst productivities. In general, catalyst productivities were approximately 20,000 Ib PE /Ib catalyst or more. The productivity of the INEOS ES -757 in Example D was similar to the productivity of the Davison 957 in Example E. However, the FI of the Davison 957 polymer was lower, and if compensation were made for this by adding oxygen to the reactor to return the FI to about 24 dg/min, the result would have been reduced productivity. Therefore, INEO ES-757 exhibited higher productivity than the Davison 957.

[0115] Additionally, the following table shows that the inventive supported catalyst systems are able to produce resins having desired and useful properties, as shown, for example, through the flow index (h i) of the resin.

TABLE 9

[0116] 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, as along as such steps, elements, or materials, do not affect the basic and novel characteristics of the invention, additionally, they do not exclude impurities normally associated with the elements and materials used.

[0117] For the sake of brevity, 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. Additionally, within a range includes every point or individual value between its end points even though not explicitly recited. Thus, every point or individual value may serve as its own lower or upper limit combined with any other point or individual value or any other lower or upper limit, to recite a range not explicitly recited. [0118] All priority documents are herein 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. Further, all documents and references cited herein, including testing procedures, publications, patents, journal articles, etc. are herein 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.

[0119] While the invention has been described with respect to a number of embodiments and examples, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope and spirit of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims.