1
Howard C Welborn Jr: Supported polymerization catalyst. Exxon Chemical Patents, M B Kurtzman, February 28, 1989: US04808561 (464 worldwide citation)

An olefin polymerization supported catalyst comprising a support and the reaction product of a metallocene of Group 4b, 5b or 6b of the Periodic Table and an alumoxane, said reaction product formed in the presence of a support.


2
Gregory G Hlatky, Howard W Turner: Catalyst system of enhanced productivity. Exxon Chemical Patents, B C Cadenhead, M B Kurtzman, M S Spiering, October 6, 1992: US05153157 (383 worldwide citation)

This invention relates to catalyst systems, and a method for using such system, for the enhanced production of homo and copolymer products of olefin, diolefin and/or acetylenically unsaturated monomers. This invention catalyst system comprises a Group III-A element compound for improving the product ...


3
John A Ewen, Howard C Welborn Jr: Process and catalyst for producing reactor blend polyolefins. Exxon Research & Engineering Company, M B Kurtzman, June 26, 1990: US04937299 (321 worldwide citation)

Polyolefin reactor blends obtained by polymerization of ethylene and higher alpha-olefins in the presence of a catalyst system comprising two or more metallocenes and alumoxane.


4
Howard C Welborn Jr: Silicon-bridged transition metal compounds. Exxon Chemical Patents, M B Kurtzman, May 21, 1991: US05017714 (307 worldwide citation)

Silicon-bridged transition metal compounds and their use as .alpha.-olefin polymerization catalysts are disclosed. A chiral silicon-bridged metallocene catalyst polymerizes .alpha.-olefins to high isotacity with a minimum of inversions at high rates of catalyst activity. The catalyst is easily made ...


5
John A Ewen, Howard C Welborn Jr: Process and catalyst for producing polyethylene having a broad molecular weight distribution. Exxon Research & Engineering Co, M B Kurtzman, July 23, 1985: US04530914 (276 worldwide citation)

Polyolefins having a broad molecular weight distribution are obtained by polymerizing ethylene or higher alpha-olefins in the presence of a catalyst system comprising two or more metallocenes each having different propagation and termination rate constants and alumoxane.


6
Jo Ann M Canich: Process for producing crystalline poly-.alpha.-olefins with a monocyclopentadienyl transition metal catalyst system. Exxon Chemical Patents, M B Kurtzman, June 25, 1991: US05026798 (267 worldwide citation)

The invention is a catalytic process using a Group IV B transition metal component and an alumoxane component to polymerize .alpha.-olefins to produce high crystallinity and high molecular weight poly-.alpha.-olefins.


7
Howard W Turner: New polymerization catalyst. Exxon Chemical Patents, M B Kurtzman, June 21, 1988: US04752597 (241 worldwide citation)

An olefin polymerization catalyst comprising the reaction product of a metallocene complex of Group IVB, VB, VIb, and VIII of the Periodic Table and an excess of alumoxane.


8
Howard C Welborn Jr: Supported polymerization catalyst. Exxon Chemical Patents, M B Kurtzman, October 20, 1987: US04701432 (233 worldwide citation)

An olefin polymerization catalyst comprising (a) a supported transition metal containing component comprising the support treated with at least one metallocene and at least one non-metallocene transition metal compound, and a cocatalyst comprising an alumoxane and an organometallic compound of a met ...


9
Elvin L Hoel: Process for production of a high molecular weight ethylene a-olefin elastomer with a metallocene alumoxane catalyst. Exxon Chemical Patents, M B Kurtzman, October 3, 1989: US04871705 (224 worldwide citation)

Disclosed is a process for preparing high molecular weight ethylene-.alpha.-olefin elastomers, preferably an ethylene-propylene elastomer, by liquid phase polymerization of the requisite monomers in the presence of a metallocene/alumoxane catalyst system. Preferably, the process is carried out as a ...


10
Howard W Turner, Gregory G Hlatky, Henry W H Yang, Avinash C Gadkari, Gary F Licciardi: Block copolymers from ionic catalysts. Exxon Chemical Patents, C L Bell, M B Kurtzman, M S Spiering, February 21, 1995: US05391629 (170 worldwide citation)

A process for the production of block copolymers of ethylene and an .alpha.-olefin such as propylene by using an ionic catalyst system including a metallocene component and a component having a cation capable of donating a proton and a compatible non-coordinating anion. Novel block copolymers are pr ...