Olefin based polymers such as polyethylene and/or polypropylene are produced via various catalyst systems. Selection of such catalyst system used in the polymerization process of the olefin based polymers is an important factor contributing to the characteristics and properties of such olefin based polymers.
Polyethylene is known for use in the manufacture of a wide a variety of articles. The polyethylene polymerization process can be varied in a number of respects to produce a wide variety of resultant polyethylene resins having different physical properties that render the various resins suitable for use in different applications. It is generally known that polyethylene can be produced in one or more conventional reactors e.g. loop reactors, spherical reactors, isothermal reactors, fluidized bed gas phase reactors, stirred tank reactors, batch reactors, in parallel, series, and/or any combinations thereof. In solution phase reactors, the ethylene monomers and optional one or more comonomers are present in a liquid diluent, such as an alkane or isoalkane, for example isobutane.
Despite the research efforts in developing catalyst systems suitable for polyolefin, such as polyethylene and/or polypropylene, polymerization, there is still a need for a pro-catalyst and a catalyst system exhibiting high selectivity toward ethylene at higher reaction temperatures; thus, facilitating the production of higher molecular weight polymers at relatively higher reaction temperatures. Additionally, despite the research efforts in developing polyolefins, such as polyethylene and/or polypropylene, with improved properties, there is still a need for a polyethylene having improved properties.
High temperature, olefin polymerization catalysts that polymerize ethylene with very high selectivity in the presence of alpha-olefins (and particularly, 1-octene) are desirable. Catalyst of this type can be used to produce ethylene-based polymers with high molecular weight and zero long chain branching at high reactor temperatures with very high efficiency. However, the development of new resins is expected to require catalysts with even higher selectivity towards ethylene in the presence alpha olefins (i.e. 1-octene) while sustaining high molecular weight capability and efficiency at least 190° C. reactor temperatures than currently available catalysts.
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