A modified Ziegler-Natta procatalyst that is a product mixture of modifying an initial Ziegler-Natta procatalyst with a molecular (pro)catalyst, and optionally an activator, the modifying occurring before activating the modified Ziegler-Natta procatalyst with an activator and before contacting the modified Ziegler-Natta procatalyst with a polymerizable olefin. Also, a modified catalyst system prepared therefrom, methods of preparing the modified Ziegler-Natta procatalyst and the modified catalyst system, a method of polymerizing an olefin using the modified catalyst system, and a polyolefin product made thereby.

A modified Ziegler-Natta procatalyst that is a product mixture of modifying an initial Ziegler-Natta procatalyst with a molecular (pro)catalyst, and optionally an activator, the modifying occurring before activating the modified Ziegler-Natta procatalyst with an activator and before contacting the modified Ziegler-Natta procatalyst with a polymerizable olefin. Also, a modified catalyst system prepared therefrom, methods of preparing the modified Ziegler-Natta procatalyst and the modified catalyst system, a method of polymerizing an olefin using the modified catalyst system, and a polyolefin product made thereby.

Provided are bimodal linear low density polyethylene copolymers (B-LLDPE copolymers) that have a combination of improved properties comprising at least one processability characteristic similar or better than that of an unblended monomodal ZN-LLDPE and a dart impact property similar or better than that of an unblended monomodal MCN-LLDPE. For the various aspects, the B-LLDPE copolymer has a density from 0.8900 to 0.9300 g/cm.sup.3; a melt index (I.sub.2) from 0.1 g/10 min. to 5 g/10 min.; a M.sub.z from 600,000 to 1,200,000 g/mol; and a hexane extractables content present in a value of up to 2.6 wt. % as measured according to ASTM D-5227:95. The B-LLDPE copolymer can be further characterized by a first melt flow ratio (I.sub.21/I.sub.2) from 25 to 65 and a first molecular weight ratio (M.sub.z/M.sub.w) from 3.5 to 5.5.

Provided are bimodal linear low density polyethylene copolymers (B-LLDPE copolymers) that have a combination of improved properties comprising at least one processability characteristic similar or better than that of an unblended monomodal ZN-LLDPE and a dart impact property similar or better than that of an unblended monomodal MCN-LLDPE. For the various aspects, the B-LLDPE copolymer has a density from 0.8900 to 0.9300 g/cm.sup.3; a melt index (I.sub.2) from 0.1 g/10 min. to 5 g/10 min.; a M.sub.z from 600,000 to 1,200,000 g/mol; and a hexane extractables content present in a value of up to 2.6 wt. % as measured according to ASTM D-5227:95. The B-LLDPE copolymer can be further characterized by a first melt flow ratio (I.sub.21/I.sub.2) from 25 to 65 and a first molecular weight ratio (M.sub.z/M.sub.w) from 3.5 to 5.5.

The present invention provides a process for the preparation of a multimodal polyethylene comprising: (i) polymerising ethylene and optionally an α-olefin comonomer in a first polymerisation stage to produce a first ethylene polymer; and (ii) polymerising ethylene and optionally an α-olefin comonomer, in the presence of said first ethylene polymer, in a second polymerisation stage, wherein the first and second polymerisation stages are carried out in the presence of an unsupported metallocene catalyst and each polymerisation stage produces at least 5% wt of the multimodal polyethylene, and the multimodal polyethylene has a multimodal molecular weight distribution, a molecular weight of at least 50,000 g/mol and a bulk density of at least 250 g/dm.sup.3, and wherein a solution of the unsupported metallocene catalyst in a solvent is employed. The present invention also provides a multimodal polyethylene, a process for preparing a pipe comprising preparing a multimodal polyethylene and extruding the multimodal recycle polyethylene to produce a pipe, and a pipe obtained by such a process.

The present invention provides a process for the preparation of a multimodal polyethylene comprising: (i) polymerising ethylene and optionally an α-olefin comonomer in a first polymerisation stage to produce a first ethylene polymer; and (ii) polymerising ethylene and optionally an α-olefin comonomer, in the presence of said first ethylene polymer, in a second polymerisation stage, wherein the first and second polymerisation stages are carried out in the presence of an unsupported metallocene catalyst and each polymerisation stage produces at least 5% wt of the multimodal polyethylene, and the multimodal polyethylene has a multimodal molecular weight distribution, a molecular weight of at least 50,000 g/mol and a bulk density of at least 250 g/dm.sup.3, and wherein a solution of the unsupported metallocene catalyst in a solvent is employed. The present invention also provides a multimodal polyethylene, a process for preparing a pipe comprising preparing a multimodal polyethylene and extruding the multimodal recycle polyethylene to produce a pipe, and a pipe obtained by such a process.

The present invention relates to a cable jacket composition comprising a multimodal olefin copolymer, said copolymer having density of 0.935-0.960 g/cm.sup.3 and MFR.sub.2 of 2.2-10.0 g/10 min and said composition having ESCR of at least 2000 hours and a cable shrinkage of 0.70% or lower. The invention further relates to the process for preparing said composition and its use as outer jacket layer for a cable, preferably a communication cable, most preferably a fiber optic cable.

The present invention relates to a cable jacket composition comprising a multimodal olefin copolymer, said copolymer having density of 0.935-0.960 g/cm.sup.3 and MFR.sub.2 of 2.2-10.0 g/10 min and said composition having ESCR of at least 2000 hours and a cable shrinkage of 0.70% or lower. The invention further relates to the process for preparing said composition and its use as outer jacket layer for a cable, preferably a communication cable, most preferably a fiber optic cable.

In various embodiments, a polyethylene formulation has a density of greater than 0.940 g/cm.sup.3 when measured according to ASTM D792, and a high load melt index (I.sub.21) of 1.0 g/10 min to 10.0 g/10 min when measured according to ASTM D1238 at 190° C. and a 21.6 kg load. Moreover, the polyethylene formulation has a peak molecular weight (M.sub.p(GPC)) of less than 50,000 g/mol, a number average molecular weight (M.sub.n(GPC)) of less than 30,000 g/mol, and a weight fraction (w1) of molecular weight (MW) less than 10,000 g/mol of less than or equal to 10.5 wt %, as determined by Gel Permeation Chromatography (GPC). Articles made from the polyethylene formulation, such as articles made by blow molding processes are also provided.

The present application relates to a process for producing a multimodal polyethylene composition comprising the steps of polymerizing a polyethylene fraction (A-1) having a weight average molecular weight Mw of equal to or more than 500 kg/mol to equal to or less than 10,000 kg/mol and a density of equal to or more than 915 kg/m.sup.3 to equal to or less than 960 kg/m.sup.3 in one reaction step and polymerizing a polyethylene fraction (A-2) having a lower weight average molecular weight Mw as polyethylene fraction (A-1) and a density of equal to or more than 910 kg/m.sup.3 to equal to or less than 975 kg/m.sup.3 in a second reaction step of a sequential multistage process wherein one of said polyethylene fractions is polymerized in the presence of the other of said polyethylene fractions to form a first polyethylene resin (A) having a weight average molecular weight Mw of equal to or more than 150 kg/mol to equal to or less than 1,500 kg/mol, and a density of equal to or more than 910 kg/m.sup.3 to equal to or less than 975 kg/m.sup.3, wherein the weight average molecular weight Mw of the first polyethylene resin (A) is lower than the weight average molecular weight Mw of the polyethylene fraction (A-1), blending the first polyethylene resin (A) with a second polyethylene resin (B) having a weight average molecular weight Mw of equal to or more than 50 kg/mol to less than 500 kg/mol, and a density of equal to or more than 910 kg/m.sup.3 to equal to or less than 970 kg/m.sup.3 to form said multimodal polyethylene composition, wherein the multimodal polyethylene composition a melt flow rate MFR.sub.5 (190° C., 5 kg) of 0.01 to 10 g/10 min and a density of equal to or more than 910 kg/m.sup.3 to equal to or less than 970 kg/m.sup.3 a polyethylene composition obtainable by said process and the polyethylene resin of said first polymerization step.