Polymerization of olefins with bridged metallocene catalysts

Details Polymerization of olefins with bridged metallocene catalysts Polymerization of olefins with bridged metallocene catalysts

1998-06-12

2001-01-23

Wu, David W. (Department: 1713)

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

Synthetic resins

Polymers from only ethylenic monomers or processes of...

C526S161000, C526S172000, C526S943000

Reexamination Certificate

active

06177529

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to bridged metallocene compounds. More particularly, it relates to bridged dicyclopentadienide derivatives of Group IVb metals. It also relates to the use thereof in catalyst systems for the polymerization of olefins.
2. Description of the Prior Art
Metallocene catalysts suffer from a disadvantage in that the polyolefin product has small particle size and low bulk density. There is therefore a need in the art for a catalyst system that would retain advantages for metallocene catalyst systems but eliminate the above-mentioned disadvantage thereof.
Morphology improvements have generally been obtained by immobilizing the metallocene on an inorganic carrier or on an organic functionally active carrier, for the purpose of heterogenization.
U.S. Pat. Nos. 5,145,819 and 5,243,001 and EP-A-582195 disclose bridged metallocenes wherein alkoxy substituents can be attached directly to the bridge.
EP-A-608054 generically discloses bridged metallocenes wherein the bridge may have as substituent a 1-20 C hydrocarbyl containing oxygen, phosphorus, nitrogen or sulphur.
SUMMARY OF THE INVENTION
Accordingly, an object of this invention is to provide bridged metallocenes for use in catalyst systems which produce polyolefins with little or no small particle size.
Another object of this invention is to provide bridged metallocenes for use in catalyst systems which produce polyolefins with high bulk density.
A further object is to provide bridged metallocenes which when used do not give reactor fouling or crust formation.
These and other objects are accomplished by the use of a neutral electron-donor substituent on the bridge of bridged metallocenes as described and claimed below.


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“Stereospecific Olefin Polymerization with Chiral Metallocene Catalysts”, H.H. Brintzinger et al, Agnew, Chem. Int. Ed. Engl., vol. 34, p. 1143-1170 (1995).
Halterman, R. L., Synthesis and Applications of Chiral Cyclopentadienylmetal Complexes,Chem. Rev. 92, pp. 965-994, 1992.
Hawley's Condensed Chemical Dictionary, John Wiley & Sons, p. 94, 1997.

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