The invention relates to a catalyst composition for the polymerization of olefins, in which the catalyst is produced using a metal-containing compound having the formula (I): MeR.sub.nX.sub.3-n (I), in which X is a halogen, Me is a metal of group III of Mendelejev's Periodic Table of Elements, R is a hydrocarbon moiety comprising>2 carbon atoms, and n is 1≦n<3, or a dimer of a compound of formula (I); and the average particle size of the catalyst as reflected by D.sub.50 (measured according to ISO13320) is between 0.5 and 4.5 μηη. The invention also relates to a process for production of said catalyst composition. The invention further relates to ultra-high molecular weight polyethylene produced via a polymerization process using said catalyst composition.

A process for preparing a solid pre-catalyst component for use in olefinic polymerization includes dissolving a magnesium chloride in an alcohol and optionally adding water to form a first solution having a water content of about 0.5 mmol water per mol MgCl.sub.2 to about 100 mmol water per mol MgCl.sub.2; contacting the first solution with a first titanium compound to form the solid pre-catalyst component; and treating the solid pre-catalyst component with a hydrocarbon or halogenated hydrocarbon solvent, optionally containing a second titanium compound.

A process for preparing a solid pre-catalyst component for use in olefinic polymerization includes dissolving a magnesium chloride in an alcohol and optionally adding water to form a first solution having a water content of about 0.5 mmol water per mol MgCl.sub.2 to about 100 mmol water per mol MgCl.sub.2; contacting the first solution with a first titanium compound to form the solid pre-catalyst component; and treating the solid pre-catalyst component with a hydrocarbon or halogenated hydrocarbon solvent, optionally containing a second titanium compound.

A polyethylene powder having a limiting viscosity [η] of 2.0 dl/g or more and less than 20.0 dl/g as measured in decalin at 135° C., wherein the polyethylene powder presents a percentage decrease from a specific surface area A measured by the BET method before heating at 120° C. for 5 h to a specific surface area B measured by a BET method after heating at 120° C. for 5 h, ((A−B)/A×100), of 0.1% or more and less than 35%.

A polyethylene powder having a limiting viscosity [η] of 2.0 dl/g or more and less than 20.0 dl/g as measured in decalin at 135° C., wherein the polyethylene powder presents a percentage decrease from a specific surface area A measured by the BET method before heating at 120° C. for 5 h to a specific surface area B measured by a BET method after heating at 120° C. for 5 h, ((A−B)/A×100), of 0.1% or more and less than 35%.

An activated solid catalyst component is disclosed formed from a magnesium compound, a titanium compound, an organosilicon compound, a supportive electron donor, and at least one internal electron donor. The solid catalyst component is activated to include titanium and carbon bonds by reaction with an activation agent, such as an aluminum compound. In one embodiment, small amounts of polymer are polymerized with the catalyst component during activation. The activated catalyst component is stable and, when formed, can later be used to produce various polyolefin polymers. The activated catalyst component has controlled reaction kinetics so that the catalyst does not overheat and degrade during initial polymerization.

An activated solid catalyst component is disclosed formed from a magnesium compound, a titanium compound, an organosilicon compound, a supportive electron donor, and at least one internal electron donor. The solid catalyst component is activated to include titanium and carbon bonds by reaction with an activation agent, such as an aluminum compound. In one embodiment, small amounts of polymer are polymerized with the catalyst component during activation. The activated catalyst component is stable and, when formed, can later be used to produce various polyolefin polymers. The activated catalyst component has controlled reaction kinetics so that the catalyst does not overheat and degrade during initial polymerization.

The polyethylene powder has an average particle diameter (D50) of 30 μm or more and 150 μm or less and a powder spreading parameter of 1.5 or more and 2.1 or less.

The polyethylene powder has an average particle diameter (D50) of 30 μm or more and 150 μm or less and a powder spreading parameter of 1.5 or more and 2.1 or less.

A process of producing a composition comprising a copolymer of ethylene and one or more C4-C8 α-olefins, may include copolymerizing the ethylene and the one or more C4-C8 α-olefins in the presence of a procatalyst and an alkylaluminum cocatalyst. The procatalyst may be a Ti-containing Ziegler Natta procatalyst and the polymerization may include the procatalyst and the alkylaluminum cocatalyst in amounts such that a molar ratio of Al:Ti ranges from about 0.5 to about 50.0.