A heterogeneous procatalyst includes a preformed heterogeneous procatalyst and a metal-ligand complex. The preformed heterogeneous procatalyst includes a titanium species and a magnesium chloride (MgCl.sub.2) support. The metal-ligand complex has a structural formula (L).sub.aM(Y).sub.m(XR.sup.2).sub.b, where M is a metal cation; each L is a neutral ligand or (?O); each Y is a halide or (C.sub.1-C.sub.20)alkyl; each XR.sup.2 is an anionic ligand in which X is a heteroatom or a heteroatom-containing functional group and R.sup.2 is (C.sub.1-C.sub.20)hydrocarbyl or (C.sub.1-C.sub.20) heterohydrocarbyl; n is 0, 1, or 2; m is 0-4; and b is 1-6. The metal-ligand complex is overall charge neutral. The heterogeneous procatalyst exhibits improved average molecular weight capability. A catalyst system includes the heterogeneous procatalyst and a cocatalyst. Processes for producing the heterogeneous procatalyst and processes for producing ethylene-based polymers utilizing the heterogeneous procatalyst are also disclosed.

An improved solid Ziegler-Natta type catalyst for the (co)polymerisation of ethylene and -olefins, particularly in high-temperature processes, such as for example adiabatic solution processes and high-pressure adiabatic processes with elevated productivity, is provided. Said catalyst is obtained by means of an original process comprising dissolving in hydrocarbons, compounds of titanium, magnesium and optionally a metal selected from hafnium and zirconium, and reprecipitating them in two steps in succession, the first of which is chlorination and the second reduction.

An improved solid Ziegler-Natta type catalyst for the (co)polymerisation of ethylene and -olefins, particularly in high-temperature processes, such as for example adiabatic solution processes and high-pressure adiabatic processes with elevated productivity, is provided. Said catalyst is obtained by means of an original process comprising dissolving in hydrocarbons, compounds of titanium, magnesium and optionally a metal selected from hafnium and zirconium, and reprecipitating them in two steps in succession, the first of which is chlorination and the second reduction.

A process for the preparation of an ultra-high molecular weight ethylene homopolymer having a MFR.sub.21 of 0.01 g/10 min or less, said process comprising: (I) prepolymerising at least ethylene at a temperature of 0 to 90? C. in the presence of a heterogeneous Ziegler Natta catalyst to prepare an ethylene prepolymer having an Mw of 40,000 to 600,000 g/mol; and thereafter in the presence of the prepolymer and said catalyst; (II) polymerising ethylene at a temperature of 55? C. or less, such as 20 to 55? C., to prepare said UHMW ethylene homopolymer; wherein the UHMW ethylene homopolymer comprises up to 8 wt. % of said prepolymer.

The present disclosure relates to novel procatalyst compositions including a titanium moiety, a magnesium halide support, a hydrocarbon solution in which the magnesium halide support is formed, and an electron donor modifier having the formula (I). The present disclosure further relates to a one-pot process for preparing the novel procatalyst compositions, as well as use of the novel procatalyst compositions in solution processes for polymerization of ethylene and at least one additional polymerizable monomer to form a polymer composition.

A polyethylene composition comprising a base resin is disclosed herein. The base resin includes an ethylene homo- or copolymer fraction (A1), and an ethylene homo- or copolymer fraction (A2). Fraction (A1) has a lower weight average molecular weight than fraction (A2). The base resin has a melt flow rate MFR.sub.21 of equal to or less than 8.0 g/10 min and a density of 930 to 950 kg/m3. The polyethylene composition has a melt flow rate MFR.sub.5 of 0.01 to 0.3 g/10 min, a flow rate ratio FRR.sub.21/5 of equal to or more than 20 and a ratio of the weight average molecular weight and the number average molecular weight (M.sub.w/M.sub.n) of equal to or less than 30. Also the polyethylene composition has a tensile modulus of less than 1000 MPa. Also a process for the production of a polyethylene composition comprising polyethylene base resin is disclosed herein.

The invention relates to a process for the production of ultra high molecular weight polyethylene in the presence of a catalyst system that comprises (I) the solid reaction product obtained from the reaction of a) a hydrocarbon solution containing 1) an organic oxygen containing magnesium compound or a halogen containing magnesium compound and 2) an organic oxygen containing titanium compound and b) an aluminium compound of the formula AIR.sub.aX(.sub.3-a) where R is a hydrocarbylgroup containing (3-10) carbon atoms, X is an halogenide and 0<a<3 and (I!) an aluminium compound having the formula AIR.sub.3 in which R is a wherein the molar ratio of aluminium from (b): titanium from (a) is higher than 3:1 and the average particle size of the catalyst ranges between 0.1 m and 1.0 m and The obtained polymer is in the form of spheroidal particles with an average particle size of less than 50 m or is in the form of loosely bound agglomerates consisting of spheroidal sub-particles with an average particle size of less than 50 m.

A process for the preparation of pre-activated or pre-polymerized catalysts made from or containing a solid catalyst component made from or containing Ti, Mg, and halogen is disclosed. The resulting catalyst is protected from the release of flammable gases in contact with water. The process includes the steps of (a) a reaction step for yielding a catalyst precursor; (b) a reaction step in which the catalyst precursor is reacted with an organoaluminum compound for yielding a modified-catalyst precursor; (c) a treatment step in which the modified-catalyst precursor is treated with a mono or polychlorinated compound, thereby yielding the solid catalyst component; and (d) isolating and recovering the solid catalyst component.

The instant invention provides a polyethylene composition and process for polymerizing the same. The polyethylene composition according to the present invention comprises the polymerization reaction of ethylene and optionally one or more -olefin comonomers in the presence of a catalyst system, wherein said polyethylene composition comprises at least 2 or more molecular weight distributions, measured via triple detector GPC low angle laser light scattering (GPC-LALLS), described in further details hereinbelow, wherein each molecular weight distribution has a peak, and wherein measured detector response of peak 1 divided by the measured detector response of peak 2 is in the range of from 0.50 to 0.79, for example from 0.55 to 0.77.

The present invention is concerned with a process for polymerizing ethylene or copolymerizing ethylene and at least one alpha-olefin comonomer in the presence of a supported polymerization catalyst in a multi-stage process in which the last polymerization stage is a gas phase reactor, the use of said process for reducing particle carry-over in the last polymerization stage and the use of a supported polymerization catalyst with a certain median particle size to polymerize an ethylene homo- or copolymer in said multi-stage process with a span of its particle size distribution which can be predicted from the median particle size of the catalyst.