This application relates to copolymer compositions and copolymerization processes, as well as to lubricating oil compositions comprising such copolymer compositions as viscosity index improvers, and base oil. The copolymer compositions may be made using two different metallocene catalysts: one capable of producing high molecular weight copolymers; and one suitable for producing lower molecular weight copolymers having at least a portion of vinyl terminations, and the copolymer compositions produced thereby. Copolymer compositions may comprise (1) a first ethylene copolymer fraction having high molecular weight, exhibiting branching topology, and having relatively lower ethylene content (based on the weight of the first ethylene copolymer fraction); and (2) a second ethylene copolymer fraction having low molecular weight, exhibiting linear rheology, and having relatively higher ethylene content (based on the weight of the second ethylene copolymer fraction). Lubricating oil compositions comprising such copolymer compositions may exhibit superior viscosity properties.

The present disclosure relates to a crosslinked polyethylene pipe having excellent physical properties. The crosslinked polyethylene pipe according to the present disclosure has optimized the degree of crosslinking and storage modulus by finding out the optimum physical property range between the degree of crosslinking and the storage modulus which have a mutual trade-off relationship, whereby the crosslinked polyethylene pipe according to the present disclosure has excellent long-term durability and short-term pressure resistance, and thus can be applied to various fields requiring these physical properties.

A continuous process for preparing an ethylene-based polyolefin, the process comprising maintaining a polymerization mixture at a temperature at or above the lower critical phase separation temperature of the polymerization mixture, while, during said step of maintaining, maintaining the polymerization mixture at steady state, where the polymerization mixture is substantially uniform in temperature, pressure, and concentration, where the polymerization mixture includes solvent, monomer including ethylene and optionally monomer copolymerizable with ethylene, a single-site catalyst system, and polymer resulting from the polymerization of the monomer, where the monomer and the polymer are dissolved in the solvent, and where the polymer is an ethylene-based polyolefin having a molecular weight distribution (Mw/Mn) of less than 2.30.

The present invention relates to a hybrid supported metallocene catalyst and a polyolefin preparation method using the same. Using the hybrid supported metallocene catalyst can not only significantly reduce the amount of wax produced when polymerizing olefin monomers, but can also enhance the stress cracking resistance of the polyolefin that is prepared.

A method of preparing a high-purity metallocene catalyst capable of providing various selectivities and high activities for polyolefin copolymers, wherein a metallocene compound is formed by reacting a ligand compound with a zirconium compound, and then lithium chloride as a reaction by-product included in the metallocene compound is prepared in a form of a complex compound and effectively removed in a subsequent step of extracting the catalyst, thereby effectively preparing the high-purity metallocene catalyst, is provided.

A catalyst composition and a method for preparing an olefin polymer by using the same are provided herein. In some embodiments, a catalyst composition includes a transition metal compound having a compound (A) represented by Chemical Formula 1 and a compound (B) represented by Chemical Formula 2 present in a molar ratio of 1.6:1 to 18. The catalyst composition has high activity in an olefin polymerization reaction and can contribute to a reduction of catalyst cost. The catalyst composition aides in high copolymerizability of olefin monomers, and the produced olefin polymers can exhibit excellent processability and long-term physical properties, suitable for a pipe.

The present disclosure relates to a method for preparing a supported hybrid metallocene catalyst, and the catalyst is prepared by supporting a first metallocene compound, supporting a cocatalyst by a separate-input method in which primarily adding a part at 100° C. to 150° C. and secondarily adding the rest at −5° C. to 40° C., and then supporting a second metallocene compound, thereby improving a supporting rate of the cocatalyst in the supported catalyst and maintaining high catalytic activity. Therefore, the present disclosure can effectively prepare a polyolefin with improved processability which exhibits increased molecular weight distribution while having high morphology (reduced fine powder), high bulk density and improved settling efficiency.

The polyethylene according to the present disclosure reacts with chlorine to prepare a chlorinated polyethylene having excellent processability during extrusion with a high tensile strength by implementing a molecular structure having a high content of medium molecular weight, and may also prepare a CPE compound including the chlorinated polyethylene.

The polyethylene according to the present disclosure has a short relaxation time and a uniform particle size, thereby preparing a chlorinated polyethylene excellent in chlorination productivity and glass transition temperature by reacting with chlorine. And, a PVC composition with improved impact strength may also be prepared by including the same.

Provided herein are metallocene-catalyzed polyethylene compositions that exhibit a high degree of broad orthogonal composition distribution (“BOCD”), meaning that they have a relatively high degree of short-chain branching in higher-molecular-weight chains, as compared to the short-chain branching in lower-molecular weight chains. The compositions may have 80 to 99.9 wt % units derived from ethylene and 0.1 to 20 wt % units derived from a C.sub.3 to C.sub.40 α-olefin comonomer; density from 0.925 to 0.950 g/cm.sup.3, melt index (I.sub.2.16) within the range from 0.1 to 5 g/10 min, and molecular weight distribution (Mw/Mn) within the range from 4.0 to 8.0. The polyethylene compositions may be formed any suitable polymerization method, although methods according to some embodiments may include utilizing a pre-trim catalyst slurry that is optionally combined with trim catalyst solution to achieve on-the-fly adjustment of catalyst ratios for producing these polyethylene compositions among other polyethylene compositions in a production campaign.