The present application relates to a process for producing ethylene polymer in a polymerization process comprising polymerisation of ethylene, optionally with comonomers selected from C.sub.3-C.sub.20-alpha-olefins, preferably selected from C.sub.4-C.sub.10-alpha-olefins, in the presence of a Ziegler-Natta catalyst under polymerisation conditions in at least one polymerisation stage carried out in a solution, slurry or gas-phase reactor or in combinations thereof, wherein the Ziegler-Natta catalyst comprises (A) a solid Ziegler-Natta catalyst component and (B) a cocatalyst, wherein the solid Ziegler-Natta catalyst component (A) comprises a solid support of a Mg compound, a transition metal of Group 4 to 6 and an internal electron donor.

The present invention relates to a process for producing alpha-olefin polymers in a multistage polymerization process which includes at least two gas phase polymerization reactors, wherein unreacted gas withdrawn from the second gas phase polymerization reactor is compressed in a compressor and said compressed gas is fed via a conveying gas line into an outlet between a first outlet vessel downstream of the first gas phase polymerization reactor and said second gas phase polymerisation reactor. Such a process can alleviate problems of malfunction, disturbances or plugging of the transfer lines and enables higher productivity and considerable saving of energy and equipment cost. Moreover, the production of alpha-olefin polymers with varying and tailored properties is possible.

The present invention relates to a process for producing alpha-olefin polymers in a multistage polymerization process which includes at least two gas phase polymerization reactors, wherein unreacted gas withdrawn from the second gas phase polymerization reactor is compressed in a compressor and said compressed gas is fed via a conveying gas line into an outlet between a first outlet vessel downstream of the first gas phase polymerization reactor and said second gas phase polymerisation reactor. Such a process can alleviate problems of malfunction, disturbances or plugging of the transfer lines and enables higher productivity and considerable saving of energy and equipment cost. Moreover, the production of alpha-olefin polymers with varying and tailored properties is possible.

Supported chromium catalysts containing a solid oxide and 0.1 to 15 wt. % chromium, in which the solid oxide or the supported chromium catalyst has a particle size span from 0.5 to 1.4, less than 3 wt. % has a particle size greater than 100 μm, and less than 10 wt. % has a particle size less than 10 μm, can be contacted with an olefin monomer in a loop slurry reactor to produce an olefin polymer. Representative ethylene-based polymers produced using the chromium catalysts have a HLMI of 4 to 70 g/10 min, a density from 0.93 to 0.96 g/cm.sup.3, from 150 to 680 ppm solid oxide (such as silica), from 1.5 to 6.8 ppm chromium, and a film gel count of less than 15 catalyst particle gels per ft.sup.2 of 25 micron thick film and/or a gel count of less than or equal to 50 catalyst particles of greater than 100 μm per five grams of the ethylene polymer.

Supported chromium catalysts containing a solid oxide and 0.1 to 15 wt. % chromium, in which the solid oxide or the supported chromium catalyst has a particle size span from 0.5 to 1.4, less than 3 wt. % has a particle size greater than 100 μm, and less than 10 wt. % has a particle size less than 10 μm, can be contacted with an olefin monomer in a loop slurry reactor to produce an olefin polymer. Representative ethylene-based polymers produced using the chromium catalysts have a HLMI of 4 to 70 g/10 min, a density from 0.93 to 0.96 g/cm.sup.3, from 150 to 680 ppm solid oxide (such as silica), from 1.5 to 6.8 ppm chromium, and a film gel count of less than 15 catalyst particle gels per ft.sup.2 of 25 micron thick film and/or a gel count of less than or equal to 50 catalyst particles of greater than 100 μm per five grams of the ethylene polymer.

The present invention relates to a process for preparation of a catalyst for polymerization of olefins. The catalyst has a particle size of between 5 to 30 microns with activity ranging from 3-4 Kg (co)polymer per g of catalyst and excellent hydrogen response. The method for preparation of the catalyst comprises the steps of: a) contacting a liquid magnesium complex, an electron donor, and a titanium halide compound to form a solution; b) obtaining the solid uniform catalyst particles by precipitation; and c) washing the catalyst particles to obtain solid uniform catalyst., for producing (co)polymer of ethylene with other olefins have fines less than 10 wt.%.

The present invention relates to a process for preparation of a catalyst for polymerization of olefins. The catalyst has a particle size of between 5 to 30 microns with activity ranging from 3-4 Kg (co)polymer per g of catalyst and excellent hydrogen response. The method for preparation of the catalyst comprises the steps of: a) contacting a liquid magnesium complex, an electron donor, and a titanium halide compound to form a solution; b) obtaining the solid uniform catalyst particles by precipitation; and c) washing the catalyst particles to obtain solid uniform catalyst., for producing (co)polymer of ethylene with other olefins have fines less than 10 wt.%.

Embodiments of the present disclosure are directed towards method for modifying a polymer flow index. As an example, a method for modifying a polymer flow index can include providing monomers to a polymerization reactor, providing a chromium catalyst to the polymerization reactor, and providing an active amount of a flow index modifier to the polymerization reactor, wherein the flow index modifier is selected from carbon dioxide, carbon monoxide, 2,4-hexadiene, and combinations thereof.

Embodiments of the present disclosure are directed towards method for modifying a polymer flow index. As an example, a method for modifying a polymer flow index can include providing monomers to a polymerization reactor, providing a chromium catalyst to the polymerization reactor, and providing an active amount of a flow index modifier to the polymerization reactor, wherein the flow index modifier is selected from carbon dioxide, carbon monoxide, 2,4-hexadiene, and combinations thereof.

A supported metallocene catalyst can include a silica-based carrier and an aluminum alkyl halide, a cocatalyst compound, and a metallocene compound supported in the silica-based carrier. The aluminum alkyl halide is supported at higher rate on the surface of the silica-based carrier than inside the pores, and the cocatalyst compound is supported at higher rate inside the pores of the silica-based carrier than on the surface of the silica-based carrier. Such a supported metallocene catalyst can be prepared by: (i) supporting an aluminum alkyl halide in a silica-based carrier; (ii) supporting a cocatalyst compound in the silica-based carrier in which the aluminum alkyl halide is supported; and (iii) supporting a metallocene compound in the carrier in which the aluminum alkyl halide and the cocatalyst compound are supported. Such a supported metallocene catalyst can be used to polymerize polyolefins with excellent activity and polyolefin with a uniform powder morphology.