Broad/bimodal resins with controlled comonomer distribution
AssigneeNOVA Chemicals (International) S.A.
InventorsPeter Hoang, Gail Baxter
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Abstract
Olefin polymers having a conventional comonomer incorporation, a reverse (or partial reverse) comonomer incorporation or a substantially flat comonomer incorporation with a broad, bimodal or multimodal molecular weight distribution are produced under a process using a single site catalyst with the combination of a phosphinimine and/or ketimide compound, and an aluminum compound in a cyclical controlled increase of the ratio of hydrogen to ethylene and controlled or uncontrolled decrease of the ratio of hydrogen to ethylene if plotted as a function of time.
Claims31
A process to produce a copolymer comprising 60 to 99 weight % of ethylene and from 1 to 40 weight % of one or more C3-8 alpha olefins having a Mw/Mn greater than 3 comprising polymerizing a mixture of monomers comprising 60 to 99 weight % of ethylene and from 1 to 40 weight % of one or more C3-8 alpha olefins in the presence of a catalyst comprising a catalyst of the formula:
- wherein M is a transition metal;
- C is a bulky heteroatom ligand selected from the group consisting of phosphinimine ligands and ketimide ligands;
- L is a monoanionic ligand selected from the group consisting of a cyclopentadienyl-type ligand and a bulky heteroatom ligand other than an phosphinimine ligand and a ketimide ligand;
- X is an activatable ligand;
- m is 1 or 2;
- n is 0 or 1;
- and p is an integer and the sum of m+n+p equals the valence state of M, provided that when m is 2, C may be the same or different bulky heteroatom ligands, and a cocatalyst and cyclically increasing by at least 5% (by pressure) and then decreasing the ratio of hydrogen to ethylene.
Dependencies are inferred from the claim text.