Pq Corporation

Thomas J Pullukat

Ronald S Shinomoto

Reinhard H Witt

Carl A Gillings

A method for preparing a silica supported, &agr;-olefin polymerization catalyst includes the steps of treating a silica support with an organosilane compound, contacting the silylated silica support with a transition metal compound to form an intermediate, then contacting the resulting intermediate with an alkylmagnesium alkoxide to form the catalyst. The transition metal compound is either a metal chloride or a metal chloroalkoxide, and the transition metal is selected from titanium, vanadium, and zirconium. The alkylmagnesium alkoxide may be selected from butylethylmagnesium butoxide, butylethylmagnesium 2-ethylhexoxide, butyloctylmagnesium ethoxide, or butylmagnesium propoxide. The process steps may be carried out in the presence of an aliphatic organic solvent, such as heptane, with a slurry of solids in the solvent being formed during the process steps. Catalysts produced by this process, during which the alkylmagnesium alkoxide contacts the reacting components after the transition metal compound is applied, have higher activities when compared with catalysts prepared by known processes under similar conditions.

High activity olefin polymerization catalysts

A catalyst having a high pore volume, high surface area porous silica support and a non-metallocene, Ziegler-Natta catalytic component incorporated on the silica support is provided for the production of polyolefins from .alpha.-olefins. The porous silica support is made up of silica gel particles having an average surface area of about 600 to about 800 m.sup.2 /g of silica and an average pore volume of about 2.5 to about 4.0 ml/g of silica. Preferably, the silica particles have an average surface area of about 650 to about 750 m.sup.2 /g of silica and an average pore volume of about 2.75 to about 3.25 ml/g of silica. Even more preferably, the silica particles have an average surface area of about 700 m.sup.2 /g of silica and an average pore volume of about 3.0 ml/g of silica. The catalytic component comprises a complex product of a transition metal halide and a metal alkyl which excludes cyclopentadienyl rings.

Olefin polymerization catalysts with specific silica supports

A transition metal containing catalyst having a silica-support is provided for the production of polyolefins from .alpha.-olefins that can be converted to polymer films, preferably thin films of polyolefin, which have lower defects resulting from a decreased presence of silica-containing residues from the catalyst. The catalyst has a porous silica support component and a catalytic component which may include, but is not limited to, such materials as chromium, magnesium-titanium (Ziegler-Natta type) or metallocene compounds (Metallocene catalyst type). The porous silica component of the catalyst has an average pore volume of from about 2.5 to about 3.5 ml/g and a surface area of 200 to 400 m.sup.2 /g and preferably 250 to 350 m.sup.2 /g. The average pore diameter ranges from about 285 to about 700 Angstroms and preferably 500-700 Angstroms for porous silica components having surface areas of 200 m.sup.2 /g and preferably 285-400 Angstroms for porous silica components having surface areas of 350 m.sup.2 /g. Preferably, the average particle size of the silica component may range from 44 to about 150 microns in diameter.

A process of producing supported olefin polymerization catalysts in which the support is a porous silica material containing specified amounts of alkali and alkaline metal cations, and olefin polymerization catalysts produced thereby.

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Lansdale, PA, United States of America

Thomas J Pullukat