Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
2002-06-04
2004-03-16
Choi, Ling-Siu (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C526S348000, C526S943000, C526S348200, C526S170000, C526S127000, C502S152000
Reexamination Certificate
active
06706828
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a process for producing polymers of &agr;-olefins, e.g., 1-hexene, 1-octene, 1-decene, 1-dodecene, and the like, in the presence of a metallocene catalyst, to form low molecular weight oligomers and polymers having viscosity and other physical properties suitable for synthetic lubricant applications.
2. Description of Related Art
Catalytic oligomerization of olefins is a known technique for manufacturing basestocks useful as lubricants. Efforts to improve upon the performance of natural mineral oil based lubricants by the synthesis of oligomeric hydrocarbon fluids have been the subject of important research and development in the petroleum industry for several decades, leading to recent commercial production of a number of superior poly(&agr;-olefin) synthetic lubricants (hereinafter referred to as “PAO”). These materials are primarily based on the oligomerization of &agr;-olefins, such as C
2
-C
20
olefins. Industrial research effort on synthetic lubricants has generally focused on fluids exhibiting useful viscosities over a wide range of temperature, i.e., improved viscosity index (VI), while also showing lubricity, thermal, and oxidative stability and pour point equal to or better than mineral oil. These newer synthetic lubricants provide lower friction and hence increase mechanical efficiency across the full spectrum of mechanical loads and do so over a wider range of operating conditions than mineral oil lubricants.
Well known structural and physical property relationships for high polymers as contained in the various disciplines of polymer chemistry have pointed the way to &agr;-olefins as a fruitful field of investigation for the synthesis of oligomers with the structure thought to be needed to confer improved lubricant properties thereon. Owing largely to studies on the polymerization of propene and vinyl monomers, the mechanism of the polymerization of &agr;-olefins and the effect of that mechanism on polymer structure is reasonably well understood, providing a strong resource for targeting on potentially useful oligomerization methods and oligomer structures.
A significant problem in the manufacture of synthetic lubricants is the production of lubricants in a preferred viscosity range in good yield without excessive catalyst deactivation. Frequently, it is difficult to directly produce lower viscosity range lubes without incurring lower yields due to the production of non-lubricant range materials. Methods to control molecular weight of lubricants in the oligomerization step are sought after in the art to overcome the problems in the manufacture of, particularly, lower viscosity lubricants.
U.S. Pat. No. 4,769,510 discloses that in the polymerization of propylene and higher 1-olefins, polymers that have a high degree of isotacticity and a narrow distribution of molecular weight are obtained in the presence of a catalyst system composed of a zirconium compound that is stereo-rigid and chiral and a linear or cyclic aluminoxane. The catalyst system is said to be exceptionally active.
U.S. Pat. No. 5,145,819 discloses certain 2-substituted bisindenylmetallocenes that are said to form, together with aluminoxanes as cocatalysts, a very effective catalyst system for the preparation of polyolefins of high molecular weight.
U.S. Pat. No. 5,455,365 discloses a process for the preparation of an olefin polymer using metallocenes containing specifically substituted indenyl ligands. It is said that a highly effective catalyst system for the polymerization of olefins comprises a cocatalyst, preferably an aluminoxane, and a metallocene of a given structural formula.
U.S. Pat. Nos. 5,504,232 and 5,763,542 disclose a catalyst system for the polymerization of olefins that comprises a cocatalyst, preferably an aluminoxane, and a metallocene that contains specifically substituted indenyl ligands.
U.S. Pat. No. 5,672,668 discloses a process for the preparation of an olefin polymer by polymerization or copolymerization of an olefin of the formula R
a
—CH═CH—R
b
, in which R
a
and R
b
are identical or different and are a hydrogen atom or a hydrocarbon radical having 1 to 14 carbon atoms, or R
a
and R
b
, together with the atoms connecting them, can form a ring, at a temperature of from −60° to 200° C., at a pressure of from 0.5 to 100 bar, in solution, in suspension or in the gas phase, in the presence of a catalyst formed from a metallocene of a given structural formula in the meso-form or a meso:rac mixture, with meso:rac>1:99, as transition-metal compound and a cocatalyst.
U.S. Pat. No. 5,688,887 discloses catalysts and processes to make low molecular weight, essentially terminally-unsaturated, viscous poly(1-olefin) or copoly(1-olefin) having a high terminal vinylidine content from a feed stock containing one or more 1-olefin and other volatile hydrocarbon liquids using a Ziegler catalyst made from a Group IVb metallocene and an aluminoxane cocatalyst, particularly bis(cyclopentadienyl) and bis(indenyl) titanium(IV), zirconium(IV) or hafnium(IV) compounds and methylaluminoxane. A particularly useful feedstock is said to be a refinery stream containing 1-olefins and isobutylene, which is used to make polyisobutylene. The reactive, essentially terminally-unsaturated, viscous poly(1-olefin) or copoly(1-olefin) can be functionalized to make a number of products useful as sealants, petroleum additives, adhesives, and the like by reacting the terminal vinylidine linkage with an aromatic, an epoxidation agent, a silylation agent, maleic anhydride, carbon monoxide and hydrogen, hydrogen, a halogen, a hydrohalogen, and the like.
U.S. Pat. No. 5,929,185 discloses copolymers that have a viscosity index VI of more than 160 and comprise A) from 99.0 to 99.99% by weight of C
2
-C
20
-alk-1-enes and B) from 0.01 to 1.0% by weight of C
5
-C
20
-&agr;, &ohgr;-dienes having isolated double bonds.
U.S. Pat. No. 6,043,401 discloses catalysts and processes to make low molecular weight, essentially terminally-unsaturated, viscous poly(1-olefin) or copoly(1-olefin) having a high terminal vinylidine content from a feed stock containing one or more 1-olefin and other volatile hydrocarbon liquids using a Ziegler catalyst made from a Group IVb metallocene and an aluminoxane cocatalyst, particularly bis(cyclopentadienyl) and bis(indenyl) titanium(IV), zirconium(IV) or hafnium(IV) compounds and methylaluminoxane. A particularly useful feedstock is said to be a refinery stream containing 1-olefins and isobutylene, which is used to make polyisobutylene. The reactive, essentially terminally-unsaturated, viscous poly(1-olefin) or copoly(1-olefin) can be functionalized to make a number of products said to be useful as sealants, petroleum additives, adhesives, and the like by reacting the terminal vinylidine linkage with an aromatic, an epoxidation agent, a silylation agent, maleic anhydride, carbon monoxide and hydrogen, hydrogen, a halogen, a hydrohalogen, and the like.
U.S. Published Appl. No. 20020010290 discloses a process for producing a polymer of an &agr;-olefin which comprises polymerizing an &agr;-olefin having at least 4 carbon atoms in the presence of a catalyst for producing polymers of olefins which comprises (A) a specific metal compound and (B) at least one compound selected from (b-1) an organoaluminum oxy compound and (b-2) an ionic compound. The polymer of an &agr;-olefin is said to be useful as a component of lubricant.
U.S. patent appl. Ser. No. 09/637,791, filed Aug. 11, 2000, describes a process for polymerizing 1-olefins to PAO with substantial saturation suitable for lubricant applications without need for further hydrogenation via the use of hydrogen with bridged cyclopentadienyl-fluorenyl metallocenes.
U.S. patent appl. Ser. No. 10/014,911, filed Dec. 14, 2001, describes a process for copolymerizing 1-olefins and 2-norbornene to PAO with substantial saturation suitable for lubricant applications without need for further hydrogenation via the use of hydrogen with bridged cyclopentadienyl-fluorenyl
Choi Ling-Siu
Crompton Corporation
Dilworth Michael P.
LandOfFree
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