Disclosed are ethylene polymer compositions containing a homogeneously-branched first ethylene polymer component and 15-35 wt. % of a homogeneously-branched second ethylene polymer component of higher density than the first ethylene polymer component. The ethylene polymer composition can be characterized by a density from 0.912 to 0.925 g/cm.sup.3, a ratio of Mw/Mn from 2 to 5, a melt index less than 2 g/10 min, and a CY-a parameter at 190° C. from 0.35 to 0.7. These polymer compositions have the excellent dart impact strength and optical properties of a metallocene-catalyzed LLDPE, but with improved machine direction tear resistance, and can be used in blown film and other end-use applications. Further, methods for improving film Elmendorf tear strength also are described.

The present invention relates to an olefin-based polymer satisfying conditions as follow: (1) a melt index (MI, 190° C., 2.16 kg load conditions) is from 0.1 g/10 min to 10.0 g/10 min, (2) a density (d) is from 0.860 g/cc to 0.880 g/cc, and (3) T(90)−T(50)≤50 and T(95)−T(90)≥10 are satisfied when measured by a differential scanning calorimetry precise measurement method (SSA). The olefin-based polymer according to the present invention is a low-density olefin-based polymer introducing a highly crystalline region and showing high mechanical rigidity.

The present invention relates to an olefin-based polymer satisfying conditions as follow: (1) a melt index (MI, 190° C., 2.16 kg load conditions) is from 0.1 g/10 min to 10.0 g/10 min, (2) a density (d) is from 0.860 g/cc to 0.880 g/cc, and (3) T(90)−T(50)≤50 and T(95)−T(90)≥10 are satisfied when measured by a differential scanning calorimetry precise measurement method (SSA). The olefin-based polymer according to the present invention is a low-density olefin-based polymer introducing a highly crystalline region and showing high mechanical rigidity.

A method of controlling long chain branching in an ethylene-based polymer includes polymerizing ethylene with one or more optional monomers to form an ethylene-based polymer, and controlling a degree of long chain branching (LCB) in the ethylene-based polymer. The degree of LCB ranges from 0.1 per 1000 carbon atoms in the polymer backbone to 10 per 1000 carbon atoms in the polymer backbone, as measured by .sup.13CNMR. The degree of LCB is controlled by adding one or more branched vinyl ester to the polymerizing step in an amount ranging from 0.01 mol % to 5.0 mol %, relative to total monomer content. A polymer composition contains the ethylene-based polymer. An article includes the polymer composition containing the ethylene-based polymer.

Catalyst systems and methods for making and using the same. A method of methylating a catalyst composition while substantially normalizing the entiomeric distribution is provided. The method includes slurrying the organometallic compound in dimethoxyethane (DME), and adding a solution of RMgBr in DME, wherein R is a methyl group or a benzyl group, and wherein the RMgBr is greater than about 2.3 equivalents relative to the organometallic compound. After the addition of the RMgBr, the slurry is mixed for at least about four hours. An alkylated organometallic is isolated, wherein the methylated species has a meso/rac ratio that is between about 0.9 and about 1.2.

Catalyst systems and methods for making and using the same. A method of methylating a catalyst composition while substantially normalizing the entiomeric distribution is provided. The method includes slurrying the organometallic compound in dimethoxyethane (DME), and adding a solution of RMgBr in DME, wherein R is a methyl group or a benzyl group, and wherein the RMgBr is greater than about 2.3 equivalents relative to the organometallic compound. After the addition of the RMgBr, the slurry is mixed for at least about four hours. An alkylated organometallic is isolated, wherein the methylated species has a meso/rac ratio that is between about 0.9 and about 1.2.

The present disclosure provides a process. In an embodiment, the process includes contacting ethylene and butene under polymerization conditions at a temperature greater than 125C with a catalyst system. The catalyst system includes (i) a first polymerization catalyst having the structure of Formula (III), (ii) a second polymerization catalyst having the structure of Formula (I), and (iii) a chain shuttling agent. The process includes forming an ethylene/butene multi-block copolymer having LCB/1000C greater than or equal to 0.06. The present disclosure provides the resultant composition produced by the process. In an embodiment, the composition includes an ethylene/butene multi-block copolymer having LCB/1000C greater than or equal to 0.06.

The present disclosure provides a process. In an embodiment, the process includes contacting ethylene and butene under polymerization conditions at a temperature greater than 125C with a catalyst system. The catalyst system includes (i) a first polymerization catalyst having the structure of Formula (III), (ii) a second polymerization catalyst having the structure of Formula (I), and (iii) a chain shuttling agent. The process includes forming an ethylene/butene multi-block copolymer having LCB/1000C greater than or equal to 0.06. The present disclosure provides the resultant composition produced by the process. In an embodiment, the composition includes an ethylene/butene multi-block copolymer having LCB/1000C greater than or equal to 0.06.

Embodiments of a polyethylene composition are provided, which may include a first polyethylene fraction comprising at least one peak in a temperature range of from 35° C. to 70° C. in an elution profile via improved comonomer composition distribution (iCCD) analysis method, where a first polyethylene area fraction is an area in the elution profile from 35° C. to 70° C., and where the first polyethylene fraction area comprises from 25% to 65% of the total area of the elution profile; and a second polyethylene fraction comprising at least one peak in a temperature range of from 85° C. to 120° C. in the elution profile, where a second polyethylene area fraction is an area in the elution profile from 85° C. to 120° C., and where the second polyethylene fraction area comprises at least 20% of the total area of the elution profile.

Embodiments of a polyethylene composition are provided, which may include a first polyethylene fraction comprising at least one peak in a temperature range of from 35° C. to 70° C. in an elution profile via improved comonomer composition distribution (iCCD) analysis method, where a first polyethylene area fraction is an area in the elution profile from 35° C. to 70° C., and where the first polyethylene fraction area comprises from 25% to 65% of the total area of the elution profile; and a second polyethylene fraction comprising at least one peak in a temperature range of from 85° C. to 120° C. in the elution profile, where a second polyethylene area fraction is an area in the elution profile from 85° C. to 120° C., and where the second polyethylene fraction area comprises at least 20% of the total area of the elution profile.