Abstract: Polyethylene is made by (co)polymerizing ethylene in a gas-phase reactor using a catalyst system comprising a chromium catalyst and a Group 4 transition metal catalyst, co-supported on an inorganic oxide support. The Group 4 transition metal catalyst is defined by the formula shown, wherein M is a Group 4 metal, PI is a phosphinimide or ketimide ligand (shown), L is a monoanionic ligand which is a cyclopentadienyl or a bulky heteroatom type ligand, m is 1 or 2, n is 0 or 1, and p is an integer. The co-supported catalyst system gives access to polyethylene having a broad or bimodal molecular weight distribution. In the copolymerization of ethylene, reversed or partially reversed comonomer distribution is achieved: the Group 4 component provides polymer segments having higher molecular weight and also higher comonomer incorporation than polymer segments produced at the chromium sites.

Abstract: Polyethylene is made by (co)polymerizing ethylene in a gas-phase reactor using a mixed catalyst system comprising a chromium catalyst supported on silica and a Group 4 transition metal catalyst, separately supported on silica. The Group 4 transition metal catalyst is defined by the formula shown, wherein M is a Group 4 metal, PI is a phosphinimide or ketimide ligand (shown), L is a monoanionic ligand which is a cyclopentadienyl or a bulky heteroatom type ligand, m is 1 or 2, n is 0 or 1, and p is an integer. The mixed catalyst system gives access to polyethylene having a broad or bimodal molecular weight distribution. In the copolymerization of ethylene, reversed or partially reversed comonomer distribution is achieved: the supported Group 4 component provides polymer segments having higher molecular weight and also higher comonomer incorporation than polymer segments produced at the supported chromium sites.

Abstract: A thermal sensor incorporating an improved retention clip is disclosed herein. The improved retention clip is both easily fabricated from either sheet stock or wire stock and is designed to be easily and securely assembled to the sensor housing and provides a convenient easy to use retention system for attaching the sensor to a tubular or generally cylindrical conduit member. The retention clip includes a gently angled lead-in portion which aids in guiding the clip into the conduit with little force coupled with a more sharply angled retention portion that substantially increases the force required to dislodge the sensor once assembled. Additionally, the clips are designed to minimize contact surface engagement with the conduit so as to minimize crevice corrosion. Portions of the clips may be covered with a suitable material to further limit the possibility of localized corrosion as well as to insulate the clip from the conduit member while also resisting relative movement therebetween.