Mixed metallocene catalyst systems containing a poor comonomer incorporator and a good comonomer incorporator
First Claim
1. A process for polymerizing olefin(s) to produce a polymer product, the process comprising contacting ethylene and at least one comonomer with a catalyst system, wherein the catalyst system comprises a poor comonomer incorporating catalyst compound comprising a metallocene structure comprising at least one fused ring cyclopentadienyl ligand bridged to another cyclopentadienyl ligand, where the bridge is a long bridge defined as a bridge containing an Si-O-Si group, and a good comonomer incorporating catalyst compound;
- wherein the poor incorporator metallocene is a polymerization catalyst which when run under process conditions wherein (Ind)2ZrCl2 would produce a 0.920 g/cm3 density polyethylene, produces a polymer with a density greater than 0.920 g/cm3;
further comprising isolating a polymer product having a density of from 0.910 to 0.940 g/cm3, an Mw/Mn value of from 2 to less than 10 and an I2 value of from 0.1 to 100 dg/min.
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Abstract
The present invention provides polymerization catalyst compounds, catalyst systems including these catalyst compounds, and to their use in the polymerization of ethylene and at least one comonomer. In particular, the invention provides a catalyst system comprising a poor comonomer incorporating catalyst compound and a good comonomer incorporating catalyst compound. Preferably, the low comonomer incorporating catalyst compound is a metallocene containing at least one substituted or unsubstituted fused ring cyclopentadienyl based ligand which is substantially directed to the front of the molecule, contains a long bridging group, or which contains a methyl substitution pattern which correlates to poor comonomer incorporation. The invention also provides methods of selecting the poor comonomer incorporating metallocene to pair with the good comonomer incorporating metallocene to produce polymers that are easy to process into a variety of articles, especially polyethylene based film, having enhanced properties.
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Citations
12 Claims
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1. A process for polymerizing olefin(s) to produce a polymer product, the process comprising contacting ethylene and at least one comonomer with a catalyst system, wherein the catalyst system comprises a poor comonomer incorporating catalyst compound comprising a metallocene structure comprising at least one fused ring cyclopentadienyl ligand bridged to another cyclopentadienyl ligand, where the bridge is a long bridge defined as a bridge containing an Si-O-Si group, and a good comonomer incorporating catalyst compound;
- wherein the poor incorporator metallocene is a polymerization catalyst which when run under process conditions wherein (Ind)2ZrCl2 would produce a 0.920 g/cm3 density polyethylene, produces a polymer with a density greater than 0.920 g/cm3;
further comprising isolating a polymer product having a density of from 0.910 to 0.940 g/cm3, an Mw/Mn value of from 2 to less than 10 and an I2 value of from 0.1 to 100 dg/min. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
- wherein the poor incorporator metallocene is a polymerization catalyst which when run under process conditions wherein (Ind)2ZrCl2 would produce a 0.920 g/cm3 density polyethylene, produces a polymer with a density greater than 0.920 g/cm3;
Specification