Processes for producing an activated chromium catalyst are disclosed, and these processes comprise contacting a supported chromium catalyst with a gas stream containing from 25-60 vol % oxygen at a peak activation temperature of 550-900° C. to produce the activated chromium catalyst. The linear velocity of the gas stream is 0.18-0.4 ft/sec, and the oxygen linear velocity of the gas stream is 0.05-0.15 ft/sec. The resultant activated chromium catalyst and an optional co-catalyst can be contacted with an olefin monomer and an optional olefin comonomer in a polymerization reactor system under polymerization conditions to produce an olefin polymer.

Processes for producing an activated chromium catalyst are disclosed, and these processes comprise contacting a supported chromium catalyst with a gas stream containing from 25-60 vol % oxygen at a peak activation temperature of 550-900° C. to produce the activated chromium catalyst. The linear velocity of the gas stream is 0.18-0.4 ft/sec, and the oxygen linear velocity of the gas stream is 0.05-0.15 ft/sec. The resultant activated chromium catalyst and an optional co-catalyst can be contacted with an olefin monomer and an optional olefin comonomer in a polymerization reactor system under polymerization conditions to produce an olefin polymer.

The present invention relates to a hybrid supported metallocene catalyst including at least first metallocene compound, at least one second metallocene compound, at least one cocatalyst compound, and a carrier, a preparation method therefor, and a polyolefin resin polymerized in the presence of the catalyst, wherein the second metallocene compound is a compound of a bridged structure having a ligand of an asymmetric structure, and the polyolefin resin has a density of 0.910 g/cm.sup.3 to 0.960 g/cm.sup.3, a molecular weight density in a unimodal distribution of 3 to 5, a melt index of 0.05 to 100 at 2.16 kg, and a melt flow rate of 20 to 40.

The present invention relates to a hybrid supported metallocene catalyst including at least first metallocene compound, at least one second metallocene compound, at least one cocatalyst compound, and a carrier, a preparation method therefor, and a polyolefin resin polymerized in the presence of the catalyst, wherein the second metallocene compound is a compound of a bridged structure having a ligand of an asymmetric structure, and the polyolefin resin has a density of 0.910 g/cm.sup.3 to 0.960 g/cm.sup.3, a molecular weight density in a unimodal distribution of 3 to 5, a melt index of 0.05 to 100 at 2.16 kg, and a melt flow rate of 20 to 40.

The present invention describes a metallocene catalyst based on a transition metal of group 4 or 5 of the periodic table, supported on a hybrid catalytic support provided with aliphatic organic groups, and a process for supporting metallocene on the hybrid catalytic support. The supported metallocene catalyst provides an ethylene polymer with broad or bimodal molecular weight distribution, in the presence of only one metallocene complex on the support.

The present invention describes a metallocene catalyst based on a transition metal of group 4 or 5 of the periodic table, supported on a hybrid catalytic support provided with aliphatic organic groups, and a process for supporting metallocene on the hybrid catalytic support. The supported metallocene catalyst provides an ethylene polymer with broad or bimodal molecular weight distribution, in the presence of only one metallocene complex on the support.

A pre-catalyst composition comprising: a) a silica support comprising silica wherein an amount of silica is in a range of from about 70 wt. % to about 95 wt. % based upon a total weight of the silica support; b) a titanium-containing compound wherein an amount of titanium is in a range of from about 0.1 wt. % to about 10 wt. % based upon the total weight of the silica support; c) a chromium-containing compound wherein an amount of chromium is in a range of from about 0.1 wt. % to about 10 wt. % based upon the total weight of the silica support; d) a surfactant wherein the surfactant comprises a non-ionic surfactant, a cationic surfactant, or a combination thereof, e) a carboxylate wherein the carboxylate comprises a multi carboxylate, an alpha-hydroxy carboxylate, or a combination thereof, and f) a solvent.

A pre-catalyst composition comprising: a) a silica support comprising silica wherein an amount of silica is in a range of from about 70 wt. % to about 95 wt. % based upon a total weight of the silica support; b) a titanium-containing compound wherein an amount of titanium is in a range of from about 0.1 wt. % to about 10 wt. % based upon the total weight of the silica support; c) a chromium-containing compound wherein an amount of chromium is in a range of from about 0.1 wt. % to about 10 wt. % based upon the total weight of the silica support; d) a surfactant wherein the surfactant comprises a non-ionic surfactant, a cationic surfactant, or a combination thereof, e) a carboxylate wherein the carboxylate comprises a multi carboxylate, an alpha-hydroxy carboxylate, or a combination thereof, and f) a solvent.

A process for producing polyethylene polymers including contacting ethylene and at least one C.sub.3 to C.sub.8 alpha-olefin comonomer with a polymerization catalyst on a particulate support in a fluidized bed polymerization reactor under conditions effective to polymerize at least part of the ethylene and comonomer and produce the polyethylene polymers, wherein the support has a d.sub.10 particle size as measured by laser diffraction of at least 18 microns, is provided.

A Ziegler-Natta catalyst component precursor made from or containing a mechanical mixture of (a) distinct particles of adducts of formula MgCl.sub.2(R.sup.1OH).sub.n where R is a C.sub.1-C.sub.8 alkyl group and n is from 0.2 to 6 having average particle size (P50a) ranging from 5 to 100 μm; and (b) from 0.2 to 5.0% by weight of distinct particles of a solid compound containing more than 50% by weight of Sift units and having average particle size (P50b), wherein the ratio P50b/P50a ranges from 0.4 to 1.5.