Olefin polymerization process
View Patent ↗A process for polymerizing ethylene is disclosed. The process comprises polymerizing ethylene in a slurry reaction in the presence of a catalyst system which comprises an activator and an indenoindolyl transition metal complex on a support material. The catalyst system is slurried with an inert solvent prior to addition to the reactor. The process provides polyethylene with good bulk density.
1. A process which comprises polymerizing ethylene in a slurry reaction in the presence of a catalyst system which comprises an activator and an indenoindolyl transition metal complex on a support, wherein the activator is selected from the group consisting of alumoxanes, organoboranes, ionic borates, and combinations thereof, and the catalyst system is slurried with an inert solvent prior to addition and added as a slurry to the reactor to produce polyethylene having a bulk density at least 15% greater than that of polyethylene made under the same conditions but without slurrying the catalyst system with an inert solvent
wherein the indenoindolyl transition metal complex has a structure selected from the group consisting of:
wherein M is a Group 3 to 10 transition metal; each L is independently selected from the group consisting of halide, alkoxy, aryloxy, siloxy, alkylamino, and C 1 -C 30 hydrocarbyl; L′ is selected from the group consisting of alkylamido, substituted or unsubstituted cyclopentadienyl, indenyl, boraaryl, pyrrolyl, azaborolinyl and indenoindolyl; x satisfies the valence of M; R 1 is selected from the group consisting of C 1 -C 30 hydrocarbyl, dialkylboryl and trialkylsilyl; each R 2 is independently selected from the group consisting of C 1 -C 30 hydrocarbyl, H, F, Cl, and Br; G is a divalent radical selected from the group consisting of hydrocarbyl and heteroatom-containing alkylene radicals, diorganosilyl radicals, diorgano-germanium radicals, organoboranyl radicals, organophoshinyl radicals, and diorganotin radicals.
2. The process of claim 1 wherein the catalyst system is slurried with from 2 to 500 mL of inert solvent per gram of catalyst system prior to addition to the reactor.
3. The process of claim 2 wherein the catalyst system is slurried with from 10 to 100 mL of inert solvent per gram of catalyst system prior to addition to the reactor.
4. The process of claim 1 wherein the support is silica.
5. The process of claim 4 wherein the activator is combined with the silica prior to addition of the indenoindolyl transition metal complex to the silica.
6. The process of claim 1 wherein L′ is selected from the group consisting of substituted or unsubstituted cyclopentadienyl, indenyl, and indenoindolyl.
7. The process of claim 1 wherein the activator is methylalumoxane.
8. The process of claim 1 comprising polymerizing ethylene in the presence of a second olefin.
9. The process of claim 1 wherein the polymerization is performed at a temperature within the range of about 30° C. to about 100° C.