Method for preparing a supported catalyst system and its use...

Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...

Reexamination Certificate

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C526S129000, C526S901000, C526S159000

Reexamination Certificate

active

06346586

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a method for preparing a supported catalyst system and for its use in a process for polymerizing olefin(s). In particular, the invention is directed to a method for preparing a supported bulky ligand metallocene-type catalyst system.
BACKGROUND OF THE INVENTION
Advances in polymerization and catalysis have resulted in the capability to produce many new polymers having improved physical and chemical properties useful in a wide variety of superior products and applications. With the development of new catalysts the choice of polymerization-type (solution, slurry, high pressure or gas phase) for producing a particular polymer has been greatly expanded. Also, advances in polymerization technology have provided more efficient, highly productive and economically enhanced processes. Especially illustrative of these advances is the development of technology utilizing bulky ligand metallocene-type catalyst systems. In particular, in a slurry or gas phase process where typically a supported catalyst system is used, there are a variety of different methods described in the art for supporting bulky ligand metallocene-type catalyst systems.
Illustrative methods for producing supported bulky ligand metallocene-type catalyst systems include: U.S. Pat. Nos. 5,332,706 and 5,473,028 have resorted to a particular technique for forming a catalyst by incipient impregnation; U.S. Pat. Nos. 5,427,991 and 5,643,847 describe the chemical bonding of non-coordinating anionic activators to supports; U.S. Pat. No. 5,492,975 discusses polymer bound metallocene-type catalyst systems; PCT publication WO 97/06186 published Feb. 20, 1997 teaches removing inorganic and organic impurities after formation of the metallocene-type catalyst itself; PCT publication WO 97/15602 published May 1, 1997 discusses readily supportable metal complexes; U.S. Pat. No. 4,937,217 generally describes a mixture of trimethylaluminum and triethylaluminum added to an undehydrated silica then adding a metallocene catalyst; EP-308177-B1 generally describes adding a wet monomer to a reactor containing a metallocene, trialkylaluminum and undehydrated silica; U.S. Pat. Nos. 4,912,075, 4,935,397 and 4,937,301 generally relate to adding trimethylaluminum to an undehydrated silica and then adding a metallocene to form a dry supported catalyst; U.S. Pat. No. 4,914,253 describes adding trimethylaluminum to undehydrated silica, adding a metallocene and then drying the catalyst with an amount of hydrogen to produce a polyethylene wax; U.S. Pat. Nos. 5,008,228, 5,086,025 and 5,147,949 generally describe forming a dry supported catalyst by the addition of trimethylaluminum to a water impregnated silica to form alumoxane in situ and then adding the metallocene; U.S. Pat. Nos. 4,808,561, 4,897,455 and 4,701,432 describe techniques to form a supported catalyst where the inert carrier, typically silica, is calcined and contacted with a metallocene(s) and a activator/cocatalyst component; U.S. Pat. No. 5,238,892 describes forming a dry supported catalyst by mixing a metallocene with an alkyl aluminum then adding undehydrated silica; and U.S. Pat. No. 5,240,894 generally pertains to forming a supported metallocene/alumoxane catalyst system by forming a metallocene/alumoxane reaction solution, adding a porous carrier, and evaporating the resulting slurry to remove residual solvent from the carrier.
U.S. Pat. No. 5,914,289 discusses making a supported catalyst system by combining a specific bulky ligand metallocene-type catalyst system with alumoxane to form a reaction product in the presence of a carrier and then heating the reaction product/carrier combination to a high temperature.
While all these methods have been described in the art, a need for an improved method for preparing a supported bulky-ligand metallocene-type catalysts has been discovered.
SUMMARY OF THE INVENTION
This invention provides a method of making a new and improved supported bulky ligand metallocene-type catalyst system and for its use in a polymerizing process.
In one embodiment, the invention is directed to a method for making a supported catalyst system comprising the steps of (a) heating a composition comprising a bulky ligand metallocene-type catalyst compound; and (b) combining the heated composition with a carrier. In this embodiment, the carrier is optionally heated and combined with the heated composition, and then dried.
In another aspect, the method comprises the steps of (a) forming a reaction product comprising a bulky ligand metallocene-type catalyst compound and an activator; (b) heating the reaction product; (c) combining a carrier, optionally heating the carrier, with the reaction product.
In yet another embodiment, the invention is directed to a method for making a supported catalyst system comprising the steps of (a) heating an activated bulky ligand metallocene-type catalyst; (b) heating a carrier; and (c) combining the heated carrier and the heated activated bulky ligand metallocene-type catalyst.
In a further embodiment, the invention relates to a method for preparing a supported catalyst system comprising the steps of (a) heating a composition comprising a bulky ligand metallocene-type catalyst compound at a first temperature; (b) heating a carrier at a second temperature; and (c) combining (a) and (b) at a third temperature. The first, second and third temperatures are the same or different.
In another embodiment, the invention is directed to a process for polymerizing olefin(s), particularly in a gas phase or slurry phase process, utilizing any one of the supported catalyst systems prepared above.
DETAILED DESCRIPTION OF THE INVENTION
Introduction
The invention is directed toward a method for making a supported catalyst system. It has been suprisingly discovered that by combining a heated bulky ligand metallocene-type catalyst system with a carrier, optionally heating the carrier, results in an increase in catalyst productivity. This method is particular enhanced when the bulky ligand metallocene-type catalyst compound has reduced solubility as compared for example with a very basic unsubstituted bulky ligand metallocene-type catalyst compound, i.e. bis(cyclopentadienyl)zirconium dichloride. The method of the invention is especially well suited for use with bridged bulky ligand metallocene-type catalyst compounds. Thus, as a result the improved method of the invention provides a way to increase catalyst productivities to a commercially acceptable level with improved reactor process operability.
Bulky Ligand Metallocene-Type Catalyst Compounds
Generally, bulky ligand metallocene-type catalyst compounds include half and full sandwich compounds having one or more bulky ligands bonded to at least one metal atom. Typical bulky ligand metallocene-type compounds are generally described as containing one or more bulky ligand(s) and one or more leaving group(s) bonded to at least one metal atom. In one preferred embodiment, at least one bulky ligands is &eegr;-bonded to the metal atom, most preferably &eegr;
5
-bonded to the metal atom.
The bulky ligands are generally represented by one or more open, acyclic, or fused ring(s) or ring system(s) or a combination thereof. These bulky ligands, preferably the ring(s) or ring system(s) are typically composed of atoms selected from Groups 13 to 16 atoms of the Periodic Table of Elements, preferably the atoms are selected from the group consisting of carbon, nitrogen, oxygen, silicon, sulfur, phosphorous, germanium, boron and aluminum or a combination thereof. Most preferably the ring(s) or ring system(s) are composed of carbon atoms such as but not limited to those cyclopentadienyl ligands or cyclopentadienyl-type ligand structures or other similar functioning ligand structure such as a pentadiene, a cyclooctatetraendiyl or an imide ligand. The metal atom is preferably selected from Groups 3 through 15 and the lanthanide or actinide series of the Periodic Table of Elements. Preferably the metal is a transition metal from Groups 4 through 12, more preferably Groups 4

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