Catalyst systems for producing polyolefins having a broad molecular weight distribution
AssigneeFina Technology, Inc.
InventorJohn A. Ewen
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Abstract
The invention provides catalyst systems for use in the polymerization of olefins to produce a polymer product having a broad molecular weight distribution. The catalyst system includes at least two different chiral, stereo-rigid metallocene catalysts of the formula R"(C.sub.5 (R').sub.4).sub.2 MeQp and an aluminum compound, preferably an alumoxane. These catalyst systems are especially useful in the polymerization of propylene.
Claims10
A catalyst system for the polymerization and copolymerization of olefins having 3-8 carbon atoms, said system comprising:
- (a) at least two different metallocene catalysts which are chiral and stereo-rigid and are described by the formula:
- R"(C.sub.5 (R').sub.4).sub.2 MeQ.sub.p
- wherein (C.sub.5 (R').sub.4) is a cyclopentadienyl or substituted cyclopentadienyl ring;
- each R' is the same or different and is a hydrogen or hydrocarbyl radical having 1-20 carbon atoms;
- R" is a structural bridge between the two (C.sub.5 (R').sub.4) rings imparting stereo-rigidity to said catalyst, and R" is selected from the group consisting of an alkylene radical having 1-4 carbon atoms, a silicon hydrocarbyl radical, a germanium hydrocarbyl radical, a phosphorus hydrocarbyl radical, a nitrogen hydrocarbyl radical, a boron hydrocarbyl radical, and an aluminum hydrocarbyl radical;
- Me is a group 4b, 5b, or 6b metal as designated in the Periodic Table of Elements;
- each Q is a hydrocarbyl radical having 1-20 carbon atoms or is a halogen;
- 0.ltoreq.p.ltoreq.3;
- and in at least one of said metallocene catalyst Me is hafnium;
- and
- (b) an organoaluminum compound selected from the group consisting of alumoxane, trimethyl aluminum, and mixtures thereof.
A catalyst system for the polymerization and copolymerization of olefins having 3-8 carbon atoms, said system comprising:
- (a) at least two different metallocene catalysts which are chiral and stereo-rigid and are described by the formula:
- R"(C.sub.S (R').sub.4).sub.2 MeQ.sub.p
- wherein (C.sub.5 (R').sub.4) is a cyclopentadienyl or substituted cyclopentadienyl ring;
- each R' is the same or different and is a hydrogen or hydrocarbyl radical having 1-20 carbon atoms;
- R" is a structural bridge between the two (C.sub.5 (R').sub.4) rings imparting stereo-rigidity to said catalyst, and R" is selected from the group consisting of an alkylene radical having 1-4 carbon atoms, a silicon hydrocarbyl radical, a germanium hydrocarbyl radical, a phosphorus hydrocarbyl radical, a nitrogen hydrocarbyl radical, a boron hydrocarbyl radical, and an aluminum hydrocarbyl radical;
- Me is a group 4b, 5b, or 6b metal as designated in the Periodic Table of Elements;
- each Q is a hydrocarbyl radical having 6-20 carbon atoms or is a halogen;
- 0.ltoreq.p.ltoreq.3;
- and in at least one catalyst Me is a group 4b metal and in at least one of the other catalysts Me is a group 5b or 6b metal;
- and
- (b) an organoaluminum compound selected from the group consisting of alumoxane, trimethyl aluminum, and mixtures thereof.
Dependencies are inferred from the claim text.