A bimodal linear polyethylene composition, products made therefrom, methods of making and using same, and articles containing same.

A bimodal linear polyethylene composition, products made therefrom, methods of making and using same, and articles containing same.

The present invention relates to a novel metallocene catalyst compound for the production of a polyolefin resin having a high molecular weight and a wide molecular weight distribution or a method of preparing the same, and more particularly to a metallocene catalyst compound using a ligand containing a Group 15 or 16 element having a bulky substituent or a method of preparing the same. The present invention provides a novel metallocene catalyst compound represented by Chemical Formula 1 below.
(L.sup.1){(N-L.sup.2)Z.sup.1(Y)Z.sup.2(N-L.sup.3)}(X)M  [Chemical Formula 1]

The present invention relates to a novel metallocene catalyst compound for the production of a polyolefin resin having a high molecular weight and a wide molecular weight distribution or a method of preparing the same, and more particularly to a metallocene catalyst compound using a ligand containing a Group 15 or 16 element having a bulky substituent or a method of preparing the same. The present invention provides a novel metallocene catalyst compound represented by Chemical Formula 1 below.
(L.sup.1){(N-L.sup.2)Z.sup.1(Y)Z.sup.2(N-L.sup.3)}(X)M  [Chemical Formula 1]

Methods for olefin polymerization are described. The methods include a) forming a first polyolefin under a first set of polymerization conditions in the presence of a first catalyst composition and a first concentration of at least a first continuity additive composition, the first polyolefin composition having a target density, ρ.sub.1, and a target Flow Index, FI.sub.1; and b) forming a second polyolefin composition under a second set of polymerization conditions in the presence of a second catalyst composition and a second concentration of a second continuity additive composition, the second polyolefin composition having a target density, ρ.sub.2, and a target Flow Index, FI.sub.2; wherein the process is essentially free of providing a polymerization neutralizing composition between steps a) and b).

Methods for olefin polymerization are described. The methods include a) forming a first polyolefin under a first set of polymerization conditions in the presence of a first catalyst composition and a first concentration of at least a first continuity additive composition, the first polyolefin composition having a target density, ρ.sub.1, and a target Flow Index, FI.sub.1; and b) forming a second polyolefin composition under a second set of polymerization conditions in the presence of a second catalyst composition and a second concentration of a second continuity additive composition, the second polyolefin composition having a target density, ρ.sub.2, and a target Flow Index, FI.sub.2; wherein the process is essentially free of providing a polymerization neutralizing composition between steps a) and b).

Disclosed is a solution polymerization process, or, alternatively, a method of delivering powder catalysts to a solution polymerization reactor, comprising combining a homogeneous single-site catalyst precursor with α-olefin monomers to form a polyolefin, wherein the homogeneous single-site catalyst precursor is in the form of (i) a dry powder, (ii) suspended in a aliphatic hydrocarbon solvent, or (iii) suspended in an oil or wax, wherein the homogeneous single-site catalyst precursor is at a concentration greater than 0.8 mmole/liter when suspended in the aliphatic hydrocarbon solvent prior to entering the solution polymerization reactor.

Disclosed is a solution polymerization process, or, alternatively, a method of delivering powder catalysts to a solution polymerization reactor, comprising combining a homogeneous single-site catalyst precursor with α-olefin monomers to form a polyolefin, wherein the homogeneous single-site catalyst precursor is in the form of (i) a dry powder, (ii) suspended in a aliphatic hydrocarbon solvent, or (iii) suspended in an oil or wax, wherein the homogeneous single-site catalyst precursor is at a concentration greater than 0.8 mmole/liter when suspended in the aliphatic hydrocarbon solvent prior to entering the solution polymerization reactor.

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.

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.