Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
1999-12-29
2002-04-30
Lipman, Bernard (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C526S133000, C526S134000, C526S161000, C502S162000
Reexamination Certificate
active
06380329
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to homopolymerization of mono-1-olefin monomers, such as ethylene and propylene, and copolymerization of a mono-1-olefin monomers, such as ethylene and propylene, with at least one higher alpha-olefin comonomer.
It is known that mono-1-olefins such, as ethylene and propylene, can be polymerized with catalyst systems employing transition metals such as titanium, vanadium, and chromium. These metallocene catalyst systems represent a new class of catalyst systems which can offer important advantages, such as high activity, hydrogen control of molecular weight, and a narrow molecular weight distribution. Most importantly these catalyst systems can allow a polymer producer to tailor the catalyst system compound to produce special, desirable characteristics in a polymer.
However, not all such metallocene catalyst systems display high activity, and most are actually too sensitive to hydrogen. The present invention relates to a new class of single site compounds which usually are not classified as metallocenes, yet offer high activity, narrow polymer molecular weight distribution, and are not so extremely sensitive to hydrogen during a polymerization reaction as a molecular weight regulator.
SUMMARY OF THE INVENTION
It is an object of this invention to provide novel catalyst systems useful for polymerization.
It is another object of this invention to provide catalyst systems which have increased activity and increased productivity.
It is a further object of this invention to provide catalyst systems which have reduced cocatalyst consumption.
It is still another object of this invention to provide an improved polymerization process.
It is yet another object of this invention to provide homopolymers of mono-1-olefins and copolymers of at least two different mono-1-olefin(s) that can be processed easily, as indicated by a narrow molecular weight distribution.
In accordance with this invention, heterogeneous or homogeneous catalyst systems comprising cyclodisilizane complexes of Group IV metals wherein said metal is selected from consisting of titanium, zirconium and hafnium; wherein said cyclodisilizane ligands further comprise substituents selected from the group consisting of alkyl, aryl, heteroatom-alkyl/aryl; wherein the heteroatom is selected from the group consisting of oxygen, nitrogen, silicon, and mixtures thereof; and wherein said cyclodisilizane complexes of Group IV metal further comprise additional ligands selected from the group consisting of halides, pseudo halides, alkyls, aryls, and mixtures thereof, and a cocatalyst selected from the group consisting of methylaluminoxane and fluoro organic boron compounds and mixtures thereof. Processes to make these catalyst systems also are provided.
In accordance with another embodiment of this invention, polymerization processes comprising contacting a mono-1-olefin, and optionally one or more higher alpha-olefins, in a reaction zone with cyclodisilizane complexes of Group IV metals catalyst systems and in the presence of a cocatalyst selected from the group consisting of aluminoxane, fluoro organic boron compounds, and mixtures thereof are provided.
In accordance with yet another embodiment of this invention catalyst systems consisting essentially of cyclodisilizane complexes of Group IV metals wherein the metal is selected from the group consisting of titanium, zirconium and hafnium; wherein said cyclodisilizane ligands further comprise substituents selected from the group consisting of alkyl, aryl, heteroatom-alkyl/aryl; wherein the heteroatom is selected from the group consisting of oxygen, nitrogen, silicon, and mixtures thereof; and wherein said cyclodisilizane complexes of Group IV metal further comprise additional ligands selected from the group consisting of halides, pseudo halides, alkyls, aryls, and mixtures thereof; and a cocatalyst selected from the group consisting of methylaluminoxane and, fluoro organic boron compounds and mixtures thereof. Processes to make these catalyst systems also are provided.
In accordance with still another embodiment of this invention, polymerization processes consisting essentially of a mono-1-olefin, and optionally one or more higher alpha-olefins, in a reaction zone with cyclodisilizane complexes of Group IV metals catalyst systems and in the presence of a cocatalyst selected from the group consisting of aluminoxane, fluoro organic boron compounds, and mixtures thereof are provided.
In accordance with yet another embodiment of this invention, compositions comprising homopolymers of mono-1-olefins and copolymers of two or more mono-1-olefins which can be characterized as having a high molecular weight, a medium density and narrow molecular weight distribution, are provided.
In accordance with yet another embodiment of this invention, compositions comprising homopolymers of ethylene and copolymers of ethylene and one or more higher alpha-olefins which can be characterized as having high molecular weight, increased branching and a narrow molecular weight distribution, are provided.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Catalyst Systems
Catalyst systems of this invention can be characterized as disilizane complexes of Group IV metals comprising additional ligands selected from the group consisting of alkyls, aryls, heteroatoms-alkyl/aryl, wherein said heteroatom is selected from the group consisting of oxygen, nitrogen, silica, and mixtures thereof and wherein additional ligands attached to the Group IV metal are selected from the group consisting of halides, pseudo halides, alkyls, aryls, and mixtures thereof. Exemplary Group IV metals include, but are not limited to, titanium, zirconium, and hafnium.
Compounds useful in accordance with this invention have a generic formula of (SiN
2
RR′
2
)
2
X
2
. These compounds can also be represented by the general structural formula shown below in Compound I
wherein R and R′ can be the same or different and are selected from the group consisting of branched or linear alkyl or aromatic groups having from about 1 to about 10, preferably from about 1 to about 8, carbon atoms per alkyl group; heteroatoms/alkyl/aryl, wherein said heteroatom is selected from the group consisting of oxygen, nitrogen, silicon and mixtures thereof; and X is selected from the group consisting of halogens, pseudo halogens, alkyls and aryls having from about 1 to about 10, preferably from about 1 to about 8, carbon atoms per alkyl or aryl group. Most preferably R′ is tertiary butyl, phenyl, or isopropyl; and wherein M is titanium, zirconium, or hafnium, preferably zirconium.
The cyclodisilizane complexes disclosed in this application can be prepared by any method known in the art. Typical syntheses of these complexes can be found in Grocholl, L., Huch, V., and Stahl, L.,
Inorg. Chem
., Vol. 36, pp. 4451-4457 (1997), herein incorporated by reference. Usually, for ease of catalyst system preparation, the cyclodisilizane ligand is prepared first. Catalyst system preparation procedures can vary, depending on substituents on the cyclodisilizane ligand.
To form an active catalyst system these compounds must be activated by combination with a cocatalyst. Suitable cocatalysts include aluminoxanes, fluoro organic boron compounds, and mixtures thereof. Aluminoxanes, also sometimes referred to as aluminoxy compounds, or poly(hydrocarbyl aluminum oxides), are well known in the art and generally are prepared by reacting a hydrocarbylaluminum compound with water. Such preparation techniques are disclosed in U.S. Pat. Nos. 3,242,099 and 4,808,561, the disclosures of which are incorporated herein by reference. The currently preferred aluminoxane cocatalysts are prepared either from trimethylaluminum or triethylaluminum and are sometimes referred to as poly(methyl aluminum oxide) and poly(ethyl aluminum oxide), respectively. It is also within the scope of the invention to use an aluminoxane in combination with a trialkylaluminum, as disclosed in U.S. Pat. No. 4,794,096, the disclosure of which is incorporated herein by refe
Farmer Kenneth R.
Jensen Michael D.
Bowman Edward L.
Harlan R.
Jolly Lynda S.
Lipman Bernard
Phillips Petroleum Company
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