This invention relates to a non-phthalate catalyst system for olefin polymerization. The non-phthalate catalyst system comprises (a) a solid Ziegler-Natta catalyst composition comprising a transition metal, a Group 2 metal, and one or more halogens; and one or more internal electron donor compounds; and (b) one or more external electron donor compounds.

Polymerization process control methods for making polyethylene are provided. The process control methods include performing a polymerization reaction in a polymerization reactor to produce the polyethylene, where ethylene, and optionally one or more comonomers, in the polymerization reaction is catalyzed by an electron donor-free Ziegler-Natta catalyst and an alkyl aluminum co-catalyst. A melt flow ratio (I.sub.21/I.sub.2) of the polyethylene removed from the polymerization reactor is measured and an amount of long chain branching (LCB) of the polyethylene from the polymerization reactor is controlled by adjusting a weight concentration of the alkyl aluminum co-catalyst present in the polymerization reactor. In addition, an electron donor-free Ziegler-Natta catalyst productivity of the polyethylene being produced in the polymerization reactor is measured from which the amount of LCB of the polyethylene from the polymerization reactor is determined using the measured electron donor-free Ziegler-Natta catalyst productivity and a predetermined relationship between the electron donor-free Ziegler-Natta catalyst productivity and the LCB.

Disclosed is a method for preparing a solid catalyst capable of controlling a molecular weight distribution and polydispersity according to an organic compound as used in a polymerization reaction, in which the solid catalyst contains titanium tetrachloride and a diester or diether organic compound. The catalyst having excellent polymerization activity, and allowing uniform particle size and high apparent density of the ultra-high molecular weight polyethylene, and easily controlling the molecular weight distribution and polydispersity of the ultra-high molecular weight polyethylene may be prepared simply and efficiently.

Disclosed is a method for preparing a titanium solid catalyst supported on magnesium dichloride that may be used to prepare ultra-high molecular weight polyethylene having a high apparent density. Performing a polymerization reaction using a solid catalyst containing titanium tetrachloride and a phthalate compound may allow ultra-high molecular weight polyethylene having uniform particle size and high apparent density to be prepared.

A solution polymerization process uses a reactor system in which a first stage is operated in a non adiabatic (cooled) manner and is connected to a second stage containing a downstream reactor that is operated adiabatically. In an embodiment, the first reactor stage includes at least one loop reactor and the second stage includes a tubular reactor. In an embodiment, the first stage is operated with a single site catalyst and at least one downstream reactor uses a Ziegler Natta catalyst.

A spherical carrier for olefin polymerization catalysts has at least one magnesium-containing compound having a structure represented by formula (1). The spherical carrier has a relatively good particle morphology, and substantially no abnormally morphological particles will appear. A method for preparing the spherical carrier can be used to prepare a carrier having a small particle size and greatly expands the particle size range of the preparable carrier. When the catalyst prepared by using the carrier is used for olefin polymerization, polymerization activity is good, substantially no abnormally morphological material is present, and hydrogen response is good.

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A spherical carrier for olefin polymerization catalysts has at least one magnesium-containing compound having a structure represented by formula (1). The spherical carrier has a relatively good particle morphology, and substantially no abnormally morphological particles will appear. A method for preparing the spherical carrier can be used to prepare a carrier having a small particle size and greatly expands the particle size range of the preparable carrier. When the catalyst prepared by using the carrier is used for olefin polymerization, polymerization activity is good, substantially no abnormally morphological material is present, and hydrogen response is good.

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A catalyst mixture made from or containing (a) particles of a solid catalyst component comprising Ti, Mg, Cl, and (b) from 0.5 to 5.0% by weight, based upon the total weight of the mixture, of particles of a solid compound having particle size ranging from 0.1 m to 1 mm containing more than 50% by weight of SiO.sub.2 units.

The present invention relates to a process for producing of solid particulate olefin polymerisation catalyst or catalyst carrier comprising forming a solution of the catalyst or a catalyst carrier in a solvent, subjecting the solution into an atomization by spraying the solution via a capillary vibrating spray nozzle with a capillary orifice having a diameter of 5 to 100 m generating a laminar jet of liquid, which disintegrates into liquid droplets entering into the spray-dryer, transforming the droplets with aid of a gas to solid particulate catalyst or carrier in the spray-dryer and recovering the solid particulate olefin polymerisation catalyst or carrier having particle size distribution defined by a volumetric SPAN of 0.7 or less. The invention further relates to the catalyst produced by the methods, and use thereof in olefin polymerisation process.

The invention relates to a polypropylene composition comprising a propylene homopolymer or propylene-ethylene copolymer having an ethylene content of at most 1.0 wt % based on the propylene-ethylene copolymer, wherein the amount of propylene homopolymer or propylene-ethylene copolymer is at least 98 wt %, for example at least 98.5 wt %, preferably at least 99 wt %, more preferably at least 99.5, for example at least 99.75 wt % based on the polypropylene composition, wherein the polypropylene composition has a melt flow rate in the range of 0.70 to 2.4 dg/min as measured according to IS01 133 (2.16 kg/230 C.), an Mw/Mn in the range from 7.0 to 13.0, wherein Mw stands for the weight average molecular weight and Mn stands for the number average weight, an Mz/Mn is in the range from 20 to 50, wherein Mz stands for the z-average molecular weight and wherein Mw, Mn and Mz are measured according to ASTM D6474-12.