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
Howard C Welborn Jr, John A Ewen: Process and catalyst for polyolefin density and molecular weight control. Exxon Chemical Patents, Myron B Kurtzman, Charles M Cox, Ben C Cadenhead, June 28, 1994: US05324800 (420 worldwide citation)

Catalysts comprising (a) derivatives of mono, bi and tricyclopentadienyl coordination complexes with a transition metal and (b) and an alumoxane are employed in a process of producing polyolefins of controlled molecular weight.


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
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 ...


7
Ferdinand C Stehling, Charles S Speed, Howard C Welborn Jr deceased: Linear ethylene interpolymer blends of interpolymers having narrow molecular weight and composition distributions. Exxon Chemical Patents, Jaimes Sher, January 17, 1995: US05382631 (177 worldwide citation)

Linear interpolymer blends are disclosed. The blends are made from components having a narrow molecular weight distribution (e.g. Mw/Mn.ltoreq.3) and a narrow composition distribution (e.g. CDBI>50%). The blend components of the blend can all have the same molecular weight but different comonomer co ...


8
Howard C Welborn Jr: Silicon-bridged transition metal compounds. June 9, 1992: US05120867 (155 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 ...


9
Howard C Welborn Jr, Charles S Speed: High pressure, high temperature polymerization of ethylene. Exxon Chemical Patents, B C Cadenhead, M B Kurtzman, January 28, 1992: US05084534 (144 worldwide citation)

A process for polymerizing or copolymerizing ethylene, either alone or in combination with other olefins, comprising contacting said ethylene or alpha-olefin, either alone or in combination with other olefins, with a catalyst comprising a cyclopentadienyl-transition metal compound and an alumoxane c ...


10
Howard C Welborn Jr: Polymerization process. Exxon Chemical Patents, M B Kurtzman, January 30, 1990: US04897455 (129 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.