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USE OF ZIEGLER-NATTA CATALYSTS MADE FROM MAGNESIUM MIXED METAL PRECURSORS

IP.com Disclosure Number: IPCOM000197587D
Publication Date: 2010-Jul-15
Document File: 4 page(s) / 20K

Publishing Venue

The IP.com Prior Art Database

Abstract

The morphology of polymer particles is very important for the production of polyolefins in gas phase and bulk slurry phase processes that include UNIPOL™, Spheripol, Spherizone, Hypol, Borstar, Innovene, Horizone, and Novolen. Particle morphology greatly influences production throughput as well as continuous operation of the process. Spherical or spheroid shape with narrow particle size distribution is preferred to enhance production rate and reduce potential for reactor fouling. Mechanical strength of particles is also important. Several polymerization processes, such as Spheripol and Spherizone, must rely on prepolymerization to increase particle strength in order to prevent polymer particle fracture during the polymerization process.

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USE OF ZIEGLER-NATTA CATALYSTS MADE FROM MAGNESIUM MIXED METAL PRECURSORS

The morphology of polymer particles is very important for the production of polyolefins in gas phase and bulk slurry phase processes that include UNIPOL™, Spheripol, Spherizone, Hypol, Borstar, Innovene, Horizone, and Novolen. Particle morphology greatly influences production throughput as well as continuous operation of the process. Spherical or spheroid shape with narrow particle size distribution is preferred to enhance production rate and reduce potential for reactor fouling. Mechanical strength of particles is also important. Several polymerization processes, such as Spheripol and Spherizone, must rely on prepolymerization to increase particle strength in order to prevent polymer particle fracture during the polymerization process.

The morphology of the polymer particle is primarily determined by the morphology of
the catalyst precursor. Typically, a spherical catalyst precursor produces a spherical catalyst particle that grows into a spherical polymer particle during polymerization. Thus, the success of a polymerization catalyst is dependent upon a morphology-controlled precursor that functions well.

Spherical catalyst precursors have been produced from mixed metal compositions that comprise magnesium and a transition metal, such as titanium. Morphology-controlled catalysts have been produced from these precursors. The production of these precursors and catalysts are disclosed in US6759362, US6511935, US5371157, US5229342, US5122494, US5151399, US5146028, US5141910, US5132263, US5124298, US5066737, US5106806, US5082907, US5077357, US6825146, and US7601664.

Catalysts containing benzoate and phthalate electron donors have been made from these mixed metal precursors and have been successfully used in the UNIPOL™ PP Process. For example, SHAC™ 310 and SHAC™ 320 Catalysts manufactured by Dow Chemical are commercially available for production of propylene-based polymer and copolymers. These catalysts provide smooth and simple process operation while offering high catalyst activity, high production rate, high ethylene content random copolymer, high performance impact copolymer, and a wide range of polymer property capabilities. The unique porosity distribution in the catalyst particles and polymer particles enables production of copolymer that contains high concentration of at least one different olefin comonomer. Such copolymers tend to agglomerate and may eventually disrupt production if the sticky rubber phase is not adequately dispersed within the homopolymer phase. In addition, the robustness of catalyst particles made from the mixed metal precursors mitigate or even eliminate dependence upon prepolymerization for improving catalyst particle strength. Other gas-phase and bulk slurry polymerization processes, including Spheripol, Spherizone, Innovene, and Novolen, are able to realize the aforementioned benefits by also using the mixed metal precurs...