Abstract: Disclosed are an ethylene polymerization process, a catalyst for use in the process, a production method employing the catalyst, and a product produced thereby. More specifically, disclosed is a process of producing an ethylene copolymer from ethylene and an alpha-olefin comonomer, in which the produced ethylene copolymer has a multimodal molecular weight distribution and excellent processability and physical properties, and thus can increase the value and productivity of products, including pipes and films. Particularly, the produced ethylene copolymer has a trimodal or higher molecular weight distribution or density distribution, and thus, when it is a linear low-density copolymer, it has an excellent effect of improving the impact strength of films, and when it is a medium-density ethylene copolymer, it can be produced into pipes, which have slow crack growth rate and can be used even at high temperature.

Abstract: Disclosed herein is a group IV transition metal catalyst for producing an ethylene homopolymer or an ethylene-olefin copolymers, having high catalytic activity, which includes a cyclopentadiene derivative and one or more anionic ligands having an aryl group substituted with an aryl derivative at an ortho-position thereof around a transition metal, the ligands not being crosslinked to each other, a catalyst system including the group IV transition metal catalyst and an aluminoxane cocatalyst or a boron compound cocatalyst, and a method of producing ethylene homopolymers or ethylene-olefin copolymers using the catalyst system.

Abstract: The present invention relates to a bis-arylaryloxy catalyst system for the production of ethylene homopolymers or copolymers with ?-olefins, which has high catalytic activity. More particularly, it relates to a transition metal catalyst comprising a group-IV transition metal as a central metal, a cyclopentadiene derivative around the central metal, and two aryloxide ligands substituted with aryl derivatives at the ortho-positions, the ligands not being bridged to each other, as well as a catalyst system comprising said catalyst and an aluminoxane co-catalyst or a boron compound co-catalyst, and a method for producing high-molecular-weight ethylene homopolymers or copolymers with ?-olefins using the same.

Abstract: The present invention relates to a bis-arylaryloxy catalyst system for the production of ethylene homopolymers or copolymers with ?-olefins, which has high catalytic activity. More particularly, it relates to a transition metal catalyst comprising a group-IV transition metal as a central metal, a cyclopentadiene derivative around the central metal, and two aryloxide ligands substituted with aryl derivatives at the ortho-positions, the ligands not being bridged to each other, as well as a catalyst system comprising said catalyst and an aluminoxane co-catalyst or a boron compound co-catalyst, and a method for producing high-molecular-weight ethylene homopolymers or copolymers with ?-olefins using the same.

Abstract: The present invention relates to a method of preparing an ethylene polymerization catalyst, which comprises reacting a solid reaction product of magnesium halide (such as magnesium chloride), alcohol, an organic magnesium compound, and a halogen compound with a transition metal compound and an electron donor. When ethylene and a-olefin are co-polymerized by slurry polymerization in the presence of the above catalyst, the amount of wax component extracted by the polymerization solvent is very low, and the polymer particles do not agglomerate. The catalyst is prepared in the form of so uniform particles that the resultant polymer has uniform particle morphology, thus increasing bulk density.

Abstract: A negative resist composition used in a liquid-crystal display element is disclosed. The negative resist composition according to the present invention includes a binder resin consisting of a copolymer including four predetermined monomers, a (meth)acryl monomer including at least 3 (meth)acryl groups, a (meth)acryl monomer including one or two (meth)acryl groups and a photo-initiator. The negative resist composition according to the present invention may be useful to significantly increase the manufacturing yield because it shows an extremely low brittleness during a bonding process or a hot process due to good physical properties such as film retention, pattern stability, adhesion to a substrate, and chemical resistance, as well as good flexibility upon formation of the pattern.