The present invention relates to a method for preparing an ethylene-based elastic copolymer, and more particularly, to a method for preparing an ethylene-based elastic copolymer by using a catalyst composition for preparing an ethylene-based elastic copolymer, the catalyst composition comprising a binuclear constrained geometry transition metal compound, as a main catalyst, having a structural advantage to obtain a high-molecular-weight ethylene-based elastic copolymer due to a high polymerization activity and comonomer reactivity because the binuclear constrained geometry transition metal compound has a structure in which cyclopentadiene ligands of two constrained geometry catalysts are linked by 1,4-phenylene, and one or more cocatalyst compounds selected from the group consisting of an organoaluminum compound, an organoaluminoxane compound, and a boron compound.

Provided are a novel indene-based transition metal complex, a transition metal catalyst composition including the same having high catalyst activity for preparing an ethylene homopolymer or copolymers of ethylene and one or more -olefins, a method for preparing an ethylene homopolymer or copolymers of ethylene and -olefins using the same, and the thus-prepared ethylene homopolymer or copolymers of ethylene and -olefins.

The present invention relates to a process for the preparation of polyolefin-based graft copolymers comprising a first long chain branched polyolefin block and one or multiple polymer side chains. The functionalized long chain branched polyolefin is produced via the copolymerization of an olefin monomer and an olefin bearing a main group metal hydrocarbyl functionality. The invention moreover relates to polyolefin obtained by said process ends. Subsequently the graft copolymers according to the invention can be produced for example by ring-opening polymerization of cyclic monomers or by transesterification of a preformed transesterifiable polymer, especially polyesters or polycarbonates. The invention moreover relates to polyolefin-based graft copolymers obtained by said process.

Methods for determining the concentration of transition metal compounds in a solution containing more than one transition metal compound are described. Polymerization reactor systems providing real-time monitoring and control of the concentrations of the transition metal components of a multicomponent catalyst system are disclosed, as well as methods for operating such polymerization reactor systems and for improving methods of preparing the multicomponent catalyst system.

Novel copolymers having a density (D) in the range 0.895-0.910 g/cm.sup.3, a melt index MI.sub.2 (2.16 kg, 190 C.) in the range of 0.01-6 g/10 min, a Compositional Distribution Branch Index (CDBI) in the range 55-85%, and a sealing initiation temperature (SIT) and density (D) satisfying the relationship SIT(AD)B wherein A is 800 C.cm.sup.3/g and B is 650 C., wherein the SIT ( C.) is determined on a 70 m film at 0.5N/15 mm and D Is in units of g/cm.sup.3 are disclosed. The copolymers may be suitably prepared by use of metallocene catalyst systems and may be used in film applications, in particular as sealing layers for packaging applications.

The present invention provides polyolefin resin composition exhibiting excellent long term durability as well as improved properties, and an article prepared using the same.

Borate activated catalyst systems and methods for making the same for gas phase or slurry phase olefin polymerization are provided. The catalyst system can include a first catalyst comprising a borate activated mono cyclopentadienyl metallocene compound and a second catalyst comprising a supported bis cyclopentadienyl metallocene complex. A supported bis cyclopentadienyl metallocene complex can be prepared to provide a preformed, supported catalyst, wherein the supported bis cyclopentadienyl metallocene complex comprises bis(1,3-methylbutyl cyclopentadienyl) zirconium dichloride. The preformed, supported catalyst can be mixed with mineral oil or hydrocarbon solvent to form a slurry. The slurry can be mixed with a borate activated mono cyclopentadienyl metallocene compound to form the borate activated catalyst system.

The present invention provides an ultra-high molecular weight polyethylene fiber having a viscosity-average molecular weight of 1010.sup.4 to 100010.sup.4, wherein the ultra-high molecular weight polyethylene fiber has at least three melting peaks in a heating differential scanning calorimetry curve (DSC curve), and in the melting peaks, the difference between (I) a peak temperature of a melting peak appearing between 140 C. or higher and lower than 150 C. and (II) a peak temperature of a melting peak appearing between 150 C. or higher and lower than 158 C. is 10 C. or less.

An olefin polymer capable of simultaneously satisfying excellent drop impact strength and transparency, a preparation method of the same, and a film using the same, can be provided. In an embodiment, an olefin polymer comprises a plurality of polymer chains, and satisfies the following conditions: i) each polymer chain of the plurality having an average number of short chain branches (SCBs) per 1000 carbon atoms of 20/1000C or more, wherein an SCB has C2 to C7 carbon atoms, ii) a molded film of the olefin polymer having a drop impact strength of 1500 g to 2400 g as measured in accordance with ASTM D1709A, wherein the molded film having a thickness of 100 m, and iii) a molded film of the olefin polymer having a haze is 10% to 30% as measured in accordance with ASTM D1003, wherein the molded film having a thickness of 0.05 mm.

The present disclosure provides a novel transition metal compound having excellent structural stability together with polymerization reactivity, and thereby is useful as a catalyst in preparing an olefin-based polymer, particularly, a high molecular weight and low density olefin-based polymer, and a catalyst composition including the same.