Catalyst system and its use in olefin polymerization

Details Catalyst system and its use in olefin polymerization Catalyst system and its use in olefin polymerization

2000-11-16

2003-04-22

Lu, Caixia (Department: 1713)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Polymers from only ethylenic monomers or processes of...

C526S134000, C526S160000, C526S165000, C526S943000, C502S108000, C502S128000, C502S152000, C502S170000

Reexamination Certificate

active

06552137

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates generally to the field of bulky ligand metallocene catalysts and their use for olefin(s) polymerization. In particular, the invention is directed to a catalyst system with enhanced activity, which includes a bulky ligand metallocene catalyst compound and a method for preparing such a system. More specifically, the present invention is directed to a catalyst system comprising a bulky ligand metallocene catalyst compound, an activator compound, a Group 13 element containing first modifier, and a cycloalkadiene second modifier, to a method of preparing such a catalyst system, and for its use in the polymerization of olefin(s).
BACKGROUND OF THE INVENTION
Numerous catalysts and catalyst systems have been developed that provide polyolefins with certain advantageous properties. One class of these catalysts are now commonly referred to as metallocenes. Metallocenes are broadly defined as organometallic coordination complexes containing one or more moieties in association with a metal atom from Groups 3 to 17 or the Lanthanide series of the Periodic Table of Elements. These catalysts are highly useful in the preparation of polyolefins, allowing one to closely tailor the final properties of a polymer.
Although metallocene catalysts are used extensively to obtain polyolefins with molecular weight, polydispersity, melt index, and other properties well suited for a desired application, the use of these catalysts is expensive. It is therefore an object of this invention to increase the activity of metallocene catalyst systems and thereby reduce the cost associated with utilizing such a system.
Organoborate and boron compounds are known as activators for olefin polymerization systems. The use of these compounds as activators, instead of alumoxane compounds, to form active olefin polymerization catalysts is documented in the literature. Marks (Marks
et al
. 1991) reported such a transformation for olefin polymerization using Group 4 metallocene-catalysts containing alkyl leaving groups activated with tris(pentafluorophenyl)borane. Similarly, Chien
et al.
(1991) activated a dimethyl zirconium catalyst with tetra(pentafluorophenyl)borate. However, when Chien used methylalumoxane (MAO) as well as the borate for the activation of the dimethyl zirconium catalyst for the polymerization of propylene, only a small amount of polymer was produced.
U.S. Pat. No. 5,747,406 discloses an increased catalytic activity when using indene or other cycloalkadienes with a half-sandwich transition metal catalyst and MAO as the activating activator. This catalyst composition demonstrates enhanced activity in the polymerization of olefins. For the polymenezation of ethylene/1-hexene using indenyl zirconium tris(diethyl-carbamate), modified MAO and indene, the addition of indehe increased the activity of the system 3.5 times.
In spite of the advances in the prior art, there exists a need to provide for a highly active metallocene catalyst systems, for a method for its preparation and use in the polymerization of olefin(s).
SUMMARY OF THE INVENTION
The present invention provides a catalyst system and a method for preparing a catalyst system which includes a bulky ligand metallocene catalyst compound, an activator compound, a Group 13 element containing first modifier, and a cycloalkadiene second modifier. The first and second modifiers, when utilized together, act to enhance the activity of the catalyst system. The present invention also provides a process for polymerizing olefin(s) utilizing the catalyst systems described herein.
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides a metallocene catalyst system having enhanced activity, a method for preparing this catalyst system and a method for polymerizing olefin(s) utilizing same. More specifically, the present invention provides for a catalyst system which includes a bulky ligand metallocene catalyst compound, preferably a half sandwich bulky ligand metallocene catalyst compound, an activator compound, a Group 13 element containing first modifier, and a cycloalkyldiene second modifier.
Bulky Ligand Metallocene Compounds
The catalyst system of the invention includes a bulky ligand metallocene catalyst. Bulky ligand metallocene compounds generally include both half and full sandwich compounds having one or more bulky ligands bonded to at least one metal atom. Typical bulky ligand metallocene 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. The bulky ligand metallocene compounds preferred include one unsubstituted or substituted, cyclopentadienyl ligand or cyclopentadienyl-type ligand. These types of bulky ligand metallocene compounds are also referred to as half-sandwich compounds or mono-cyclopentadienyl compounds (mono-Cps), and the terms are used interchangeably herein.
The unsubstituted or substituted, cyclopentadienyl ligand or cyclopentadienyl-type bulky ligand, is generally represented by one or more open, acyclic, or fused ring or ring system 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. The unsubstituted or substituted, cyclopentadienyl ligands or cyclopentadienyl-type ligands include heteroatom substituted and/or heteroatom containing cyclopentadienyl-type ligands.
Non-limiting examples of these bulky ligands include cyclopentadienyl ligands, cyclopentaphenanthreneyl ligands, indenyl ligands, benzindenyl ligands, fluorenyl ligands, octahydrofluorenyl ligands, cyclooctatetraendiyl ligands, cyclopentacyclododecene ligands, azenyl ligands, azulene ligands, pentalene ligands, phosphoyl ligands, phosphinimine (WO 99/40125), pyrrolyl ligands, pyrozolyl ligands, carbazolyl ligands, borabenzene ligands and the like, including hydrogenated versions thereof, for example tetrahydroindenyl ligands.
Bulky ligands which comprise one or more heteroatoms include those ligands containing nitrogen, silicon, boron, germanium, sulfur and phosphorous, in combination with carbon atoms to form an open, acyclic, or preferably a fused, ring or ring system, such as, for example, a hetero-cyclopentadienyl ancillary ligand. Other bulky ligands include but are not limited to bulky amides, phosphides, alkoxides, aryloxides, imides, carbolides, borollides, porphyrins, phthalocyanines, corrins and other polyazomacrocycles.
The cyclopentadienyl ligand or cyclopentadienyl-type bulky ligand may be unsubstituted or substituted with a combination of substituent groups R. Non-limiting examples of substituent groups R include one or more from the group selected from hydrogen, or linear, branched alkyl radicals, or alkenyl radicals, alkynyl radicals, cycloalkyl radicals or aryl radicals, acyl radicals, aroyl radicals, alkoxy radicals, aryloxy radicals, alkylthio radicals, dialkylamino radicals, alkoxycarbonyl radicals, aryloxycarbonyl radicals, carbomoyl radicals, alkyl- or dialkyl- carbamoyl radicals, acyloxy radicals, acylamino radicals, aroylamino radicals, straight, branched or cyclic, alkylene radicals, or combination thereof. In a preferred embodiment, substituent groups R have up to 50 non-hydrogen atoms, preferably from 1 to 30 carbon, that can also be substituted with halogens or heteroatoms or the like. Non-limiting examples of alkyl substituents R include methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclopentyl, cyclohexyl, benzyl or phenyl groups and the like, including all their isomers, for example tertiary butyl, isopropyl, and the like. Other hydrocarbyl radicals include fluoromethyl, fluroethyl, difluroethyl, iodopropyl, bromohexyl, chlorobenzyl and hydrocarbyl substituted organometalloid radicals including trimethylsilyl, trimethylgermyl, methyldiethylsilyl and the like; and halocarbyl-substituted organometalloid radicals including tris(trifluoromethyl)-silyl, methyl-bis(difluoromethyl)

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