Abstract:
Disclosed herein are polymerization processes for the production of olefin polymers. These polymerization processes can use a dual catalyst system containing a zirconium or hafnium based metallocene compound and a titanium based half-metallocene compound containing an indenyl group.
Abstract:
Techniques are provided for catalyst preparation. A system for catalyst preparation may include an agitator disposed inside a polymerization catalyst tank and configured to mix a polymerization catalyst and a solvent to generate a polymerization catalyst solution. The system may also include a heating system coupled to the polymerization catalyst tank and configured to maintain a temperature of the polymerization catalyst solution above a threshold. The system may also include a precontactor configured to receive feed streams comprising an activator and the polymerization catalyst solution from the polymerization catalyst tank to generate a catalyst complex. The system may also include a transfer line configured to transfer the catalyst complex from an outlet of the precontactor to a reactor.
Abstract:
The present invention provides a polymerization process utilizing a dual ansa-metallocene catalyst system. Polymers produced from the polymerization process are also provided, and these polymers have a reverse comonomer distribution, a non-bimodal molecular weight distribution, a ratio of Mw/Mn from about 3 to about 8, and a ratio of Mz/Mw from about 3 to about 6.
Abstract:
The present invention provides dual catalyst systems and polymerization processes employing these dual catalyst systems. The disclosed polymerization processes can produce olefin polymers at higher production rates, and these olefin polymers may have a higher molecular weight and/or a lower melt index.
Abstract:
A method of preparing a medium-density polyethylene pipe comprising melting a multimodal metallocene-catalyzed polyethylene resin to form a molten polyethylene, wherein the multimodal metallocene-catalyzed polyethylene resin has a density of from about 0.925 g/ml to about 0.942 g/ml, a magnitude of slip-stick greater than about 300 psi, a stress for smooth to matte transition of greater than about 90 kPa of stress, and a shear rate for smooth to matte transition greater than about 10 s−1, wherein the magnitude of slip-stick, stress for smooth to matte transition, and shear rate for smooth to matte transition are determined by a capillary rheology test; and forming the molten polyethylene resin into pipe. A pipe prepared from a multimodal metallocene-catalyzed polyethylene resin having a density of from about 0.925 g/ml to about 0.942 g/ml, a magnitude of slip-stick greater than about 300 psi; a stress for smooth to matte transition of greater than about 90 kPa, and a shear rate for smooth to matte transition greater than about 10 s−1, wherein the magnitude of slip-stick, stress for smooth to matte transition, and shear rate for smooth to matte transition are determined by a capillary rheology test.
Abstract:
Disclosed herein are polymerization processes for the production of olefin polymers. These polymerization processes use a catalyst system containing three metallocene components, often resulting in polymers having a reverse comonomer distribution and a broad and non-bimodal molecular weight distribution.
Abstract:
The present invention provides polymerization processes utilizing an ansa-metallocene catalyst system for the production of olefin polymers. Polymers produced from the polymerization processes have properties that vary based upon the presence or the absence of hydrogen and/or comonomer in the polymerization process.
Abstract:
The present invention provides a polymerization process utilizing a dual ansa-metallocene catalyst system. Polymers produced from the polymerization process are also provided, and these polymers have a reverse comonomer distribution, a non-bimodal molecular weight distribution, a ratio of Mw/Mn from about 3 to about 8, and a ratio of Mz/Mw from about 3 to about 6.
Abstract:
The present invention provides polymerization processes utilizing a catalyst system containing an ansa-metallocene and a second metallocene compound for the production of olefin polymers.
Abstract:
The present techniques relate to catalyst compositions, methods, and polymers encompassing a Group 4 metallocene compound comprising bridging η5-cyclopentadienyl-type ligands, typically in combination with a cocatalyst, and a activator. The compositions and methods presented herein include ethylene polymers with low melt elasticity.