Abstract: A composition, such as a catalyst precursor or a catalyst comprising a Cr coated silica support with particularly defined levels of Na and Al, such that the resulting Cr/Silica catalyst has an increased MI potential is disclosed. In an embodiment, the disclosed catalyst composition comprises a silica-containing substrate made using a base-set gel and comprising a catalytically active metal consisting of Cr, with Al impurities of less than 50 ppm and Na in an amount of less than 800 ppm of the catalyst composition. The disclosed composition has an increased MI potential over a catalyst having higher Al content, a lower Na:Al ratio, or both. Methods of making the disclosed composition, and methods of using it to prepare a polyethylene are also disclosed.

Abstract: A composition, such as a catalyst precursor or a catalyst comprising a Cr coated silica support with particularly defined levels of Na and Al, such that the resulting Cr/Silica catalyst has an increased MI potential is disclosed. In an embodiment, the disclosed catalyst composition comprises a silica-containing substrate made using a base-set gel and comprising a catalytically active metal consisting of Cr, with Al impurities of less than 50 ppm and Na in an amount of less than 800 ppm of the catalyst composition. The disclosed composition has an increased MI potential over a catalyst having higher Al content, a lower Na:Al ratio, or both. Methods of making the disclosed composition, and methods of using it to prepare a polyethylene are also disclosed.

Abstract: A composition, such as a catalyst precursor or a catalyst comprising a Cr coated silica support with particularly defined levels of Na and Al, such that the resulting Cr/Silica catalyst has an increased MI potential is disclosed. In an embodiment, the disclosed catalyst composition comprises a silica-containing substrate made using a base-set gel and comprising a catalytically active metal consisting of Cr, with Al impurities of less than 50 ppm and Na in an amount of less than 800 ppm of the catalyst composition. The disclosed composition has an increased MI potential over a catalyst having higher Al content, a lower Na:Al ratio, or both. Methods of making the disclosed composition, and methods of using it to prepare a polyethylene are also disclosed.

Abstract: A method for preparing a catalyst precursor for an olefin polymerization catalyst involves the use of aqueous or alcoholic solutions of a chromium salt and of boric acid and aluminium carboxylate for deposition onto an inorganic support material, such as a silica xerogel. The chromium salt, aluminium carboxylate and boric acid are sufficiently soluble for deposition from a single solution to be effective. The catalyst precursor can be activated by calcination to form a catalyst for homo- or co-polymerisation of ?-olefins which has productivity and melt flow index for the resulting polymer or copolymer which is comparable to results obtained with catalysts prepared by prior art organometallic routes. The activation of the catalyst precursor gives reduced levels of toxic or noxious fumes during activation compared to use of organometallic sources of chromium or aluminium.

Abstract: A method for preparing a catalyst precursor for an olefin polymerization catalyst involves the use of aqueous or alcoholic solutions of a chromium salt and of boric acid and aluminum carboxylate for deposition onto an inorganic support material, such as a silica xerogel. The chromium salt, aluminum carboxylate and boric acid are sufficiently soluble for deposition from a single solution to be effective. The catalyst precursor can be activated by calcination to form a catalyst for homo- or co-polymerisation of ?-olefins which has productivity and melt flow index for the resulting polymer or copolymer which is comparable to results obtained with catalysts prepared by prior art organometallic routes. The activation of the catalyst precursor gives reduced levels of toxic or noxious fumes during activation compared to use of organometallic sources of chromium or aluminum.

Abstract: A method for preparing a catalyst precursor for an olefin polymerization catalyst involves the use of aqueous or alcoholic solutions of a chromium salt and of boric acid and aluminium carboxylate for deposition onto an inorganic support material, such as a silica xerogel. The chromium salt, aluminium carboxylate and boric acid are sufficiently soluble for deposition from a single solution to be effective. The catalyst precursor can be activated by calcination to form a catalyst for homo- or co-polymerisation of ?-olefins which has productivity and melt flow index for the resulting polymer or copolymer which is comparable to results obtained with catalysts prepared by prior art organometallic routes. The activation of the catalyst precursor gives reduced levels of toxic or noxious fumes during activation compared to use of organometallic sources of chromium or aluminium.