In some embodiments, ethylene-propylene random copolymers as viscosity modifiers were synthesized with pyridyldiamido catalyst systems and a chain transfer agent. In some embodiments, the present disclosure provides for ethylene-propylene random copolymers having an ethylene content between about 45 wt % and about 55 wt %. In some embodiments, the ethylene-propylene random copolymer is used as a viscosity modifier in a lubricating composition and a fuel composition.

Embodiments of methods for producing a trimodal polymer in a solution polymerization process comprise three solution polymerization reactors organized in parallel or in series.

Disclosed are catalyst systems comprising the reaction product of at least the following: A) a procatalyst; and B) at least one cocatalyst structure selected from the following i) through iii): i) at least one cocatalyst comprising an anion having Structure 1 as shown below: ##STR00001##  as described herein; or ii) at least one cocatalyst comprising an anion having Structure 2 as shown below: ##STR00002##  as described herein; or iii) a combination of i and ii.

The present invention relates to a novel Group 4 transition metal compound, a method for preparing the compound, a catalyst composition comprising the compound, and a method for preparing a polyolefin comprising performing a polymerization reaction of olefin monomers, in the presence of the catalyst composition. Since the Group 4 transition metal compound of the present invention exhibits an excellent catalytic activity in polyolefin synthesis reactions, as well as having excellent thermal stability, it can be used for polyolefin synthesis reactions at high temperatures, and by changing the type of a central metal and ligand, the weight average molecular weight of synthesized polyolefins and the octene content in the polymer can be controlled. Therefore, it can be effectively used in polyolefin synthesis processes in which grades are controlled.

The present invention relates to a novel Group 4 transition metal compound, a method for preparing the compound, a catalyst composition comprising the compound, and a method for preparing a polyolefin comprising performing a polymerization reaction of olefin monomers, in the presence of the catalyst composition. Since the Group 4 transition metal compound of the present invention exhibits an excellent catalytic activity in polyolefin synthesis reactions, as well as having excellent thermal stability, it can be used for polyolefin synthesis reactions at high temperatures, and by changing the type of a central metal and ligand, the weight average molecular weight of synthesized polyolefins and the octene content in the polymer can be controlled. Therefore, it can be effectively used in polyolefin synthesis processes in which grades are controlled.

The instant invention provides procatalysts and catalyst systems for olefin polymerization, olefin based polymers polymerized therewith, and process for producing the same. In one embodiment, the instant invention provides a procatalyst comprising a metal-ligand complex of formula (I):

##STR00001##

Embodiments are directed to catalyst systems comprising at least one metal ligand complex and to processes for polyolefin polymerization incorporating the catalyst systems. The metal ligand complexes have the following structures: (I) ##STR00001##

Embodiments of polyethylene compositions and articles comprising polyethylene compositions are disclosed. The polyethylene compositions may include a first polyethylene fraction area defined by an area in the elution profile in a temperature range of 70° C. to 97° C. via improved comonomer composition distribution (iCCD) analysis method; a first peak in the temperature range of 70° C. to 97° C. in the elution profile; a second polyethylene fraction area defined by an area in the elution profile in a temperature range of 97° C. to 110° C.; and a second peak in the temperature range of 97° C. to 110° C. The polyethylene composition may have a density of 0.935 g/cm.sup.3 to 0.955 g/cm.sup.3 and a melt index (I.sub.2) of 1.0 g/10 minutes to 10.0 g/10 minutes. A ratio of the first polyethylene fraction area to the second polyethylene fraction area may be less than 2.0.

Processes of polymerizing olefin monomers using catalyst systems and catalysts systems that include a procatalyst having a structure according to formula (I):

The present invention relates to a process for producing a propylene polymer, such as a propylene homopolymer, a propylene-ethylene random copolymer or a heterophasic propylene copolymer using a specific class of metallocene complexes in combination with a cocatalyst system comprising a boron containing cocatalyst and an aluminoxane cocatalyst, preferably in a multistage polymerization process including a gas phase polymerization step.