Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
2000-09-06
2002-03-12
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...
C526S160000, C526S161000, C526S352000, C526S943000, C502S152000, C502S155000
Reexamination Certificate
active
06355744
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an olefin polymerization catalyst component which is an organometallic complex having three ligands, namely a cyclopentadienyl ligand, a phosphinimine ligand and only one activatable ligand.
BACKGROUND OF THE INVENTION
Certain “metallocenes” (especially bis-cyclopentadienyl complexes of group 4 metals) are highly productive catalysts for olefin polymerization when used in combination with an appropriate activator (see, for example, U.S. Pat. No. 4,542,199 (Sinn et al) and U.S. Pat. No. 5,198,401 (Hlatky and Turner).
Olefin polymerization catalysts which contain a group 4 metal and one cyclopentadienyl ligand, one phosphinimine ligand and two monoanionic activatable ligands are disclosed in a commonly assigned patent application (Stephan et al). Thus, the catalysts of Stephan et al are group 4 metals in the 4
+
oxidation state.
We have now discovered a new family of olefin polymerization catalysts which contain a group 4 metal, a cyclopentadienyl ligand or phosphinimine ligand and only one activatable ligand. A preferred family of these catalysts contains Ti(III) and offers an excellent kinetic profile when used in olefin polymerization.
SUMMARY OF THE INVENTION
The present invention provides a catalyst component for olefin polymerization which is an organometallic complex defined by the formula:
wherein Cp is a cyclopentadienyl-type ligand; L is an activatable ligand; M is a metal selected from Ti and Zr; and PI is a phosphinimine ligand defined by the formula:
wherein each R
1
is independently selected from the group consisting of a hydrogen atom, a halogen atom, C
1-20
hydrocarbyl radicals which are unsubstituted by or further substituted by a halogen atom, a C
1-8
alkoxy radical, an amido radical, a C
6-10
aryl or aryloxy radical, a silyl radical of the formula:
—Si—(R
2
)
3
wherein each R
2
is independently selected from the group consisting of hydrogen, a C
1-8
alkyl or alkoxy radical, C
6-10
aryl or aryloxy radicals, and a germanyl radical of the formula:
Ge—(R
2
)
3
wherein R
2
is as defined above.
DETAILED DESCRIPTION
1. Description of Catalyst Component
1.1 Metals
The catalyst component of this invention is a group 4 metal selected from titanium and zirconium.
1.2 Phosphinimine Ligand
The catalyst component of this invention must contain a phosphinimine ligand which is covalently bonded to the metal. This ligand is defined by the formula:
wherein each R
1
is independently selected from the group consisting of a hydrogen atom, a halogen atom, C
1-20
hydrocarbyl radicals which are unsubstituted by or further substituted by a halogen atom, a C
1-8
alkoxy radical, a C
6-10
aryl or aryloxy radical, an amido radical, a silyl radical of the formula:
—Si—(R
2
)
3
wherein each R
2
is independently selected from the group consisting of hydrogen, a C
1-8
alkyl or alkoxy radical, C
6-10
aryl or aryloxy radicals, and a germanyl radical of the formula:
Ge—(R
2
)
3
wherein R
2
is as defined above.
The preferred phosphinimines are those in which each R
1
is a hydrocarbyl radical. A particularly preferred phosphinimine is tri-(tertiary butyl) phosphinimine (i.e. where each R
1
is a tertiary butyl group).
1.3 Cyclopentadienyl-Type Ligand
The term cyclopentadienyl-type ligand (or “Cp ligand”) refers to a ligand which is cyclic and forms a delocalized pi-bond with the group 4 transition metal. An exemplary (i.e. illustrative but non-limiting) list of “Cp ligands” includes substituted (or unsubstituted) cyclopentadienyl ligands, substituted (or unsubstituted) indenyl ligands, and substituted (or unsubstituted) fluorenyl ligands.
The use of “substituents” on such cyclic ligands is well known and is described, for example, in U.S. Pat. No. 5,324,800 (Welborn). An exemplary list of substituents for such Cp ligands includes C
1-20
hydrocarbyl groups; substituted C
1-20
hydrocarbyl groups wherein one or more hydrogen atoms is replaced by a halogen; an amido group, a phosphido group, or an alkoxy group. The substituent may form a bridge with the phosphinimine ligand.
For reasons of cost and simplicity, it is especially preferred that the Cp ligand is a cyclopentadienyl or indenyl ligand.
1.4 Activatable Ligand
The term “activatable ligand” refers to a ligand which may be activated by a cocatalyst (also known as an “activator” to facilitate olefin polymerization. Exemplary activatable ligands are independently selected from the group consisting of a hydrogen atom, a halogen atom, a C
1-10
hydrocarbyl radical, a C
1-10
alkoxy radical, a C
5-10
aryl oxide radical; each of which said hydrocarbyl, alkoxy, and aryl oxide radicals may be unsubstituted by or further substituted by a halogen atom, a C
1-8
alkyl radical, a C
1-8
alkoxy radical, a C
6-10
aryl or aryl oxy radical, an amido radical which is unsubstituted or substituted by up to two C
1-8
alkyl radicals; a phosphido radical which is unsubstituted or substituted by up to two C
1-8
alkyl radicals.
2. Description of Activators (or “Cocatalysts”)
The catalyst components described in part 1 above are used in combination with an “activator” (which may also be referred to by a person skilled in the art as a “cocatalyst”) to form an active catalyst system for olefin polymerization. Simple aluminum alkyls and alkoxides may provide comparatively weak cocatalytic activity under certain mild polymerization conditions. However, the preferred activators are alumoxanes and so-called ionic activators, as described below.
2.1 Alumoxanes
The alumoxane activator may be of the formula:
(R
4
)
2
AlO(R
4
AlO)
m
Al(R
4
)
2
wherein each R
4
is independently selected from the group consisting of C
1-20
hydrocarbyl radicals and m is from 0 to 50, preferably R
4
is a C
1-4
alkyl radical and m is from 5 to 30. Methylalumoxane (or “MAO”) is the preferred alumoxane.
Alumoxanes are well known as activators for metallocene-type catalysts.
Activation with alumoxane generally requires a molar ratio of aluminum in the activator to (group 4) metal in the catalyst from 20:1 to 1000:1. Preferred ratios are from 50:1 to 250:1.
2.2 Ionic Activators
Ionic activators are also well known for metallocene catalysts. See, for example, U.S. Pat. No. 5,198,401 (Hlatky and Turner). These compounds may be selected from the group consisting of:
(i) compounds of the formula [R
5
]
+
[B(R
7
)
4
]
−
wherein B is a boron atom, R
5
is a cyclic C
5-7
aromatic cation or a triphenyl methyl cation and each R
7
is independently selected from the group consisting of phenyl radicals which are unsubstituted or substituted with from 3 to 5 substituents selected from the group consisting of a fluorine atom, a C
1-4
alkyl or alkoxy radical which is unsubstituted or substituted by a fluorine atom; and a silyl radical of the formula —Si—(R
9
)
3
; wherein each R
9
is independently selected from the group consisting of a hydrogen atom and a C
1-4
alkyl radical; and
(ii) compounds of the formula [(R
8
)
t
ZH]
+
[B(R
7
)
4
]
−
wherein B is a boron atom, H is a hydrogen atom, Z is a nitrogen atom or phosphorus atom, t is 2 or 3 and R
8
is selected from the group consisting of C
1-8
alkyl radicals, a phenyl radical which is unsubstituted or substituted by up to three C
1-4
alkyl radicals, or one R
8
taken together with the nitrogen atom may form an anilinium radical and R
7
is as defined above; and
(iii) compounds of the formula B(R
7
)
3
wherein R
7
is as defined above.
In the above compounds preferably R
7
is a pentafluorophenyl radical, and R
5
is a triphenylmethyl cation, Z is a nitrogen atom and R
8
is a C
1-4
alkyl radical or R
8
taken together with the nitrogen atom forms an anilinium radical which is substituted by two C
1-4
alkyl radicals.
The “ionic activator” may abstract the activatable ligand so as to ionize the catalyst center into a cation but not to covalently bond with the catalyst and to provide sufficient distance between the catalyst and the ionizing activator to permit a polymerizable olefin to enter the resulting active s
Brown Stephen John
Jeremic Dusan
Spence Rupert Edward von Haken
Stephan Douglas W.
Wang Qinyan
Harlan R.
Johnson Kenneth H.
Nova Chemicals (International) S.A.
Wu David W.
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