摘要:
This invention relates to catalyst compositions comprising a first metallocene compound, a second metallocene compound, at least one chemically-treated solid oxide, and at least one organoaluminum compound. This invention also relates to methods to prepare and use the catalyst compositions and new polyolefins. The compositions and methods disclosed herein provide ethylene polymers and copolymers with lower MI, increased melt strength, and good MD tear properties.
摘要:
This invention relates to the field of olefin polymerization catalyst compositions, and methods for the polymerization and copolymerization of olefins, including polymerization methods using a supported catalyst composition. In one aspect, the present invention encompasses a catalyst composition comprising the contact product of a first metallocene compound, a second metallocene compound, at least one chemically-treated solid oxide, and at least one organoaluminum compound. The new resins were characterized by useful properties in impact, tear, adhesion, sealing, extruder motor loads and pressures at comparable melt index values, and neck-in and draw-down.
摘要:
This invention relates to the field of olefin polymerization catalyst compositions, and methods for the polymerization and copolymerization of olefins, including polymerization methods using a supported catalyst composition. In one aspect, the present invention encompasses a catalyst composition comprising the contact product of a first metallocene compound, a second metallocene compound, at least one chemically-treated solid oxide, and at least one organoaluminum compound. The new resins were characterized by useful properties in impact, tear, adhesion, sealing, extruder motor loads and pressures at comparable melt index values, and neck-in and draw-down.
摘要:
This invention relates to the field of metal-catalyzed olefin polymerization methods and the polymers and films prepared therefrom. In one aspect, this invention provides polyethylene and ethylene/α-olefin copolymers formed in the presence of tightly-bridged metallocene catalyst, organoaluminum cocatalyst, and a chemically-treated solid oxide, and optionally in the presence of additional cocatalysts. The resins and films prepared from these polymers exhibit high haze values, low clarity values, and a low coefficient of friction.
摘要:
This invention relates to the field of olefin polymerization catalyst compositions, and methods for the polymerization and copolymerization of olefins, including polymerization methods using a supported catalyst composition. In one aspect, the present invention encompasses a catalyst composition comprising the contact product of a first metallocene compound, a second metallocene compound, at least one chemically-treated solid oxide, and at least one organoaluminum compound. The new resins were characterized by useful properties in impact, tear, adhesion, sealing, extruder motor loads and pressures at comparable melt index values, and neck-in and draw-down.
摘要:
This invention relates to the field of olefin polymerization catalyst compositions, and methods for the polymerization and copolymerization of olefins, including polymerization methods using a supported catalyst composition. In one aspect, the present invention encompasses a catalyst composition comprising the contact product of a first metallocene compound, a second metallocene compound, at least one chemically-treated solid oxide, and at least one organoaluminum compound. The new resins were characterized by useful properties in impact, tear, adhesion, sealing, extruder motor loads and pressures at comparable melt index values, and neck-in and draw-down.
摘要:
A method comprising (a) contacting a support and a chromium-containing compound to form chromium-containing support, (b) heat treating the chromium-containing support in an oxidizing atmosphere to form a treated support, (c) contacting the treated support with carbon monoxide to form a CO-contacted support, and (d) contacting the CO-contacted support with hydrogen to form a catalyst. A method comprising oxidizing a chromium-treated support to form a polymerization catalyst, contacting the polymerization catalyst with carbon monoxide to form a reduced polymerization catalyst, contacting the reduced polymerization catalyst with hydrogen to form an activated polymerization catalyst, and contacting the activated polymerization catalyst with ethylene in a reaction zone under suitable reaction conditions to form a random copolymer. A method comprising reducing a polymerization catalyst comprising Cr(VI) to form a polymerization catalyst comprising Cr(II), and treating the polymerization catalyst comprising Cr(II) with hydrogen.
摘要:
Silica-coated alumina activator-supports, and catalyst compositions containing these activator-supports, are disclosed. Methods also are provided for preparing silica-coated alumina activator-supports, for preparing catalyst compositions, and for using the catalyst compositions to polymerize olefins.
摘要:
The present invention provides activator-supports containing alumina-silica compounds with high levels of alumina, and polymerization catalyst compositions employing these activator-supports. Methods for making these activator-supports based on alumina-silica and for using such compounds in catalyst compositions for the polymerization and copolymerization of olefins are also provided.
摘要:
Methods of preparing a polymerization catalyst are provided that include contacting a support comprising alumina with a sulfating agent and with chromium. In an embodiment in which the chromium is provided from a chromium compound such as chromium oxide, the support may be calcined after loading the sulfating agent and the chromium on the support. Alternatively, the sulfating agent can be loaded on the support while calcining it. In another embodiment in which the chromium is provided from an organochromium compound, the support may be calcined after contacting it with the sulfating agent and before contacting it with the organochromium compound. Catalysts compositions formed by the foregoing method are provided. In an embodiment, catalyst compositions comprise chromium and a sulfate treated alumina support. The catalyst compositions have an activity for ethylene polymerization that is at least about 25% greater than an activity of the same catalyst without sulfate.