摘要:
Embodiments of the invention generally include multicomponent catalyst systems, polymerization processes and reactor blends formed by the processes. The multicomponent catalyst system generally includes a first catalyst component selected from an isotactic directing metallocene catalyst. The multicomponent catalyst system further includes a second syndiotactic directing metallocene catalyst component.
摘要:
Embodiments of the invention generally include multicomponent catalyst systems, polymerization processes and reactor blends formed by the processes. The multicomponent catalyst system generally includes a first catalyst component selected from an isotactic directing metallocene catalyst. The multicomponent catalyst system further includes a second syndiotactic directing metallocene catalyst component.
摘要:
Embodiments of the invention generally include multicomponent catalyst systems, polymerization processes and reactor blends formed by the processes. The multicomponent catalyst system generally includes a first catalyst component and a second catalyst component, wherein the second catalyst component is different from the first catalyst component.
摘要:
Supported metallocene catalysts and processes for the use of such catalysts in isotactic polymerization of a C3+ ethylenically unsaturated monomer. The supported catalysts comprise a particulate silica support, an alkyl alumoxane component, and a metallocene catalyst component. The support has an average particle size of 10-50 microns, a surface area of 200-800 m2/g and a pore volume of 0.9-2.1 milliliters per gram (ml/g). Alumoxane is incorporated onto the support to provide a weight ratio of alumoxane to silica of at least 0.8:1. The metallocene is present in an amount of at least 1 weight percent of the silica and the alumoxane and is of the formula B(CpRaRb)(Fl′)MQ2 in which Fl′ is an unsubstituted fluorenyl group or a fluorenyl group symmetrically substituted at the 3 and 6 positions, B is a structural bridge between Cp and Fl′, Ra is a bulky substituent in a distal position, Rb is a less bulky substituent proximal to the bridge and non-vicinal to the distal substituent, M is a Group IVB transition metal or vanadium, and Q is a halogen or a Cl-C4 alkyl group.
摘要:
Processes for the polymerization of olefins with Zeigler-type catalyst systems which involve transition metal catalyst components comprising 4, 5 or 6 transition metals incorporating internal electron donors to provide desired polymerization characteristics, including yield and polymer characteristics. Specific olefins used in the polymerization process are C2-C4 alpha olefins such as propylene in the production of stereoregular polypropylene. The catalyst system comprised a transition metal component having an internal electron donor in an amount providing an internal donor/transition metal mole ratio of no more than 2/3. This is combined with an organoaluminum co-catalyst component to provide a precusor mixture having an aluminum/transition metal mole ration of at least 100. The precusor mixture is combined with an organosilicon external electron donor component in an amount to provide an aluminum/silicon mole ration of no more than 200. The catalyst system is introduced to a polymerization reactor to effect polymerization of the olefin with the catalyst system.
摘要:
The invention provides a process for commercial production of syndiotactic polyolefins using a metallocene catalyst supported on silica treated with MAO. The invention includes contacting the supported metallocene catalyst with an aluminum alkyl and aging the catalyst prior to polymerization. In addition, the catalyst is prepolymerized in a tubular reactor prior to being introduced into the polymerization reaction zone. The treated silica is produced by removing water to a level of 0.5-1.08%, slurrying in a nonpolar solvent, adding an alumoxane, heating to reflux, cooling the slurry, and separating the solid product.
摘要:
Processes for the formulation of Ziegler-type catalysts from a plurality of catalyst components including transition metal, organosilicon electron donor, and organoaluminum co-catalyst components. The components are mixed together in the course of formulating the Ziegler-type catalyst to be charged to an olefin polymerization reactor. Several orders of addition of the catalyst components can be used in formulating the Ziegler catalyst. One involves mixing of the transition metal component with the organoaluminum co-catalyst to formulate a mixture having an aluminum/transition metal mole ratio of at least 200. This mixture is combined with the organosilicon electron donor component to produce a Ziegler-type catalyst formulation having an aluminum/silicon mole ratio of no more than 50. There may be an initial pre-polymerization of the catalyst prior to introducing the catalyst into an olefin polymerization reactor. The mole ratio of aluminum to silicon in the catalyst formulation within the range of 20 to 50 and the mole ratio of silicon to transition metal within the range of 10-20. Relatively short time sequences can be used in formulating the Ziegler-type catalyst. Another order of addition involves initial contact of the organoaluminum co-catalyst and the organosilicon electron donor to provide a mixture having an aluminum to silicon mole ratio of at least 10. This mixture is then combined with the transition metal component having an aluminum/transition metal mole ratio of at least 200.
摘要:
Processes for the formulation of Ziegler-type catalysts from a transition metal component, an electron donor and a co-catalyst which are sequentially mixed together. The co-catalyst is initially contacted with either of the transition metal catalyst or the electron donor for a first contact time of 5-120 seconds. This mixture is then contacted with the remainder of the electron donor or transition metal component for a second contact time of less and 110 seconds. The three component system is then used in olefin polymerization. The olefin contacting step can involve an initial pre-polymerization reaction. A specific order of addition involves mixture of the transition metal component and the co-catalyst component for a contact time of 5-120 seconds followed by contact with an electron donor component for no more than 30 seconds. Another order of addition involves initially contacting the electron donor with the co-catalyst. A further order of addition is such that the electron donor is initially contacted with the transition metal component for up to 40 seconds. The resulting mixture is then contacted with the co-catalyst component for a shorter second contact time up to 20 seconds.
摘要:
It has been discovered that using n-butylmethyldimethoxysilane (BMDS) as an external electron donor for Ziegler-Natta catalysts can provide a catalyst system that may prepare polypropylene films with improved properties. The catalyst systems of the invention provide for controlled chain defects/defect distribution and thus a regulated microtacticity. Consequently, the curve of storage modulus (G′) v. temperature is shifted such that the film achieves the same storage modulus at a lower temperature enabling faster throughput of polypropylene film through a high-speed tenter.
摘要:
The invention provides a process for commercial production of syndiotactic polyolefins using a metallocene catalyst supported on silica treated with MAO. The invention includes contacting the supported metallocene catalyst with an aluminum alkyl and aging the catalyst prior to polymerization. In addition, the catalyst is prepolymerized in a tubular reactor prior to being introduced into the polymerization reaction zone.