Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Plural component system comprising a - group i to iv metal...
Reexamination Certificate
2001-09-10
2003-09-09
Harlan, Robert D. (Department: 1713)
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Plural component system comprising a - group i to iv metal...
C502S117000, C502S118000, C502S125000, C502S132000, C502S133000, C502S152000, C526S124300, C526S156000, C526S160000, C526S904000, C526S943000
Reexamination Certificate
active
06617277
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to supported metallocene olefin polymerization catalyst systems, methods of producing the catalysts and methods of polymerizing alpha-olefins with the catalysts to form polymers having narrow molecular weight distribution. More particularly, this invention relates to the preparation of a catalyst precursor component comprising a metallocene containing transition metal compound, a magnesium containing compound, an aluminum compound, a silicon compound and a polymeric support material. The catalyst precursor component is combined with a cocatalyst and used in olefin polymerization.
BACKGROUND OF THE INVENTION
The polymerization of olefins, such as ethylene, propylene and other alpha-olefins is an important industrial process which is run on a huge scale around the world. Important factors in the polymerization process are the properties and cost of the polymer product which relate to the catalyst used in the process. The use of certain types of catalysts results in the presence of residue of catalyst components in the polymer product. In one type of polymerization process, the catalyst is prepared in situ. In other types of polymerization processes, the catalyst is fully or partially prepared before use in the polymerization process. A catalyst and its components (co-catalyst, modifiers, external electron donors, etc.) can be attached to a solid support material or the catalyst and its components can be added individually. This means that in certain types of catalyst systems, the catalyst components (co-catalyst, modifiers, external electron donors, etc.,) can be added individually to the reaction medium during the polymerization process. On the other hand, there are other cases in which the catalyst can be premixed with all its components during the catalyst preparation process resulting in the addition of one catalyst component to the reaction medium during the polymerization process.
The preparation of supported metallocene catalysts has previously been complicated and expensive. For example, the preparation of supported metallocene catalysts has required expensive and troublesome silica dehydration and aluminoxanes treatment during catalyst preparation. Procedures typically used for the preparation of silica supports such as spray drying or re-crystallization processes are complicated and expensive. Also, high calcination temperatures are required to remove water, which is a common catalyst poison. These steps represent a significant proportion of the preparation of the catalyst. In addition, the use of silica as a support results in the presence of support residue in the polymerization product, which can affect product processing and properties, such as optical properties.
Since the type of catalyst system used plays a major role in the polymerization process, the form and the physical properties of the catalyst system are important. For example, a solid catalyst system in the form of granules, often supported on silica or magnesium chloride, is usually used in gas phase and liquid slurry polymerization processes in order to reduce possible fouling of the reactor.
One of the objects of the present invention is to overcome the difficulties encountered in the prior art. The present invention provides a new development in olefin polymerizations. The supported metallocene catalyst system of the invention in which polyvinylchloride is used as a polymeric support can be used in both slurry and gas phase polymerization processes.
SUMMARY OF THE INVENTION
The present invention provides a catalyst composition comprising a catalyst component which comprises a metallocene compound, a magnesium compound, a silicon compound, a hydroxyl containing compound, an aluminum compound and a polymeric material. The silicon compound and/or aluminum compound are optional. The catalyst component, when used in conjunction with a co-catalyst such as an organoaluminum compound or a mixture of organoaluminum compounds, is useful for polymerization of ethylene to linear low and medium density polyethylenes and copolymerization of ethylene with alpha-olefins having about 3 to 18 carbon atoms. The catalyst composition has the ability to produce polymers with narrow molecular weight distributions.
DETAILED DESCRIPTION OF THE INVENTION
The catalyst composition of the present invention contains a solid catalyst component. The solid catalyst component contains at least a metallocene compound, a magnesium compound, a hydroxyl containing compound, and a polymeric material having a mean particle diameter of 5 &mgr;m to 1000 &mgr;m, a pore volume of 0.1 cc/g or above, a pore diameter of at least 10 angstroms or a pore diameter of 500 to 10,000 Angstroms and a surface area of from 0.2 m
2
/gm to 15 m
2
/gm. The solid catalyst component may also contain a silicon compound and an aluminum compound. The solid catalyst component is useful in olefin polymerization catalysts.
Metallocenes suitable for use in the invention can be represented by the general formula (Cp)
z
MR
w
X
y
wherein Cp represents a substituted or unsubstituted cyclopentadienyl ring; M represents a Group IVB or VB transition metal of the Periodic Table of the Elements (CAS Version); R represents a hydrocarbyl radical such as alkyl, said hydrocarbyl radical containing 1 to 20 carbon atoms, e.g., methyl, ethyl or propyl; X represents a halogen atom; and 1≦z≦3, 0≦w≦3, and 0≦y≦3. The cyclopentadienyl ring may be substituted with a hydrocarbyl radical such as alkyl, alkenyl or aryl, said hydrocarbyl containing 1 to 20 carbon atoms; such as methyl, ethyl, propyl, aryl, isoamyl, isobutyl, phenyl and the like. The preferred transition metals are titanium, zirconium or vanadium.
Preferred metallocene compounds include bis(cyclopentadienyl) zirconium dimethyl, bis(cyclopentadienyl)zirconium methyl chloride, bis(cyclopentadienyl) zirconium ethyl chloride and bis(cyclopentadienyl)zirconium dichloride.
The magnesium compounds used for the solid catalyst component include Grignard compounds represented by the general formula R
3
MgX, wherein R
3
is a hydrocarbyl group of 1 to 20 carbon atoms and X is a halogen atom; preferably chlorine.
The magnesium compound is preferably a reagent with the chemical formula R
a
M
g
X
2-a
wherein R is an alkyl group having 1 to 20 carbon atoms and X is halogen or alkyl group independently having 1 to 20 carbon atoms and a is 0, 1 or 2.
Other preferred magnesium compounds are represented by the general formula R
4
R
5
Mg, wherein R
4
and R
5
are the same or different hydrocarbyl group of 1 to 20 carbon atoms.
Preferred magnesium compounds include the following: dialkylmagnesium such as diethylmagnesium, dipropylmagnesium, di-iso-propylmagnesium, di-n-butylmagnesium, di-iso-butylmagnesium, butylethylmagnesium, dihexylmagnesium, dioctylmagnesium butyloctyl magnesium; alkyl magnesium chloride such as ethylmagnesium chloride, butylmagnesium chloride, hexylmagnesium chloride and the like.
A silicon compound which can be used in the synthesis of the solid catalyst component in this invention can be represented by the general formula MX
4
, wherein M is a metalloid of Group IV, preferably silicon; and X is a halogen atom, preferably chlorine.
The hydroxyl containing compound used in the synthesis of the solid catalyst component in this invention can be represented by the general formula Z
+
OH
−
or R
+
OH
−
wherein Z
+
is a metal of Groups IA to VIA, or a non metal cation, e.g.,
+
NH
4
or even H
+
. R can be a hydrocarbyl group of 1 to 20 carbon atoms, and R is preferably alkyl.
An aluminum compound can be used in small amounts in the synthesis of the solid catalyst component of this invention to treat the polymeric support after treatment with hydroxyl compound. Alkyl aluminoxanes are the preferred aluminum compounds for this treatment of the support.
The polymer particles used in the present invention have a spherical shape with a particle diameter of 5 to 1000 &mgr;m, preferably 10 to 800 &mgr;m, and more preferably 15 to 500
Abu-Raqabah Atieh
Hamed Orass
Moman Akhlaq
Harlan Robert D.
Kramer Levin Naftalis & Frankel LLP
Saudi Basic Industries Corporation
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